Outdoor Post type

Current Transformers
Equipment Specification

Document number: TES 20-09

Issue number: 4
Status: Approved
Author: Nandana Boteju
Approver: Stuart Dick
Date of approval: 27/03/2013
 SP AusNet TES 20-09

Outdoor Current Transformers –Equipment Specification

Table of Contents
1 PURPOSE ................................................................................................................................ 4

2 REFERENCES.......................................................................................................................... 4
2.1 NATIONAL AND INTERNATIONAL STANDARDS ........................................................................................ 4

2.2 SP AUSNET REFERENCE STANDARDS ........................................................................................................ 5

2.3 SP AUSNET REFERENCE DRAWINGS.......................................................................................................... 5

3 GENERAL REQUIREMENTS ................................................................................................ 5

3.1 DESCRIPTION ............................................................................................................................................. 5

3.2 CLIMATIC CONDITIONS ............................................................................................................................. 7

3.3 COMPLIANCE WITH NATIONAL ELECTRICITY RULES................................................................................. 8

4 PERFORMANCE REQUIREMENTS ..................................................................................... 8

4.1 Minimum Performance Requirements ..................................................................................................... 8

5 TECHNICAL REQUIREMENTS ..........................................................................................24

5.1 General Current Transformer Requirements ......................................................................................... 24

5.2 CONSTRUCTION....................................................................................................................................... 26

5.3 Terminating boxes, Connections and Terminal Markings...................................................................... 30

5.4 Earthing ................................................................................................................................................... 30

5.5 Rating Plates............................................................................................................................................ 31

5.6 TESTING ................................................................................................................................................... 32

5.7 TYPE TESTS............................................................................................................................................... 33

5.8 Routine Tests........................................................................................................................................... 34

5.9 TESTS AFTER DELIVERY............................................................................................................................ 36

6 SAFETY REQUIREMENTS..................................................................................................37
6.1 Insulator Housing .................................................................................................................................... 37

6.2 Insulating Liquid ...................................................................................................................................... 37

6.3 Oil sampling and filling............................................................................................................................ 37

6.4 Oil Level and Nitrogen Pressure Indicators ............................................................................................ 37

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6.5 Special Environmental: Toxicology Safety.............................................................................................. 37

APPENDIX A – DRAWINGS .......................................................................................................39

APPENDIX B – TENDER RESPONSE SCHEDULES ................................................................40

SCHEDULE 1– Guaranteed Performance Schedule - 24 kV Current Transformers (item 1)................................ 41

SCHEDULE 1– Guaranteed Performance Schedule - 24 kV Current Transformers (Item 2) ............................... 47

SCHEDULE 1 – Guaranteed Performance Schedule - 72.5 kV Current Transformers ......................................... 53

SCHEDULE 1 – Guaranteed Performance Schedule - 245 kV Current Transformers .......................................... 59

SCHEDULE 1– Guaranteed Performance Schedule - 362 kV Current Transformers ........................................... 66

SCHEDULE 1 – Guaranteed Performance Schedule - 550 kV Current Transformers (CTS with 1 Amp Secondary
Rating Cores)......................................................................................................................................................... 72

SCHEDULE 2 – Details of Plant Being Offered – 24 kV Current Transformers (Item 1)....................................... 77

SCHEDULE 2 – Details of Plant Being Offered – 24 kV Current Transformers (Item 2)....................................... 79

SCHEDULE 2 – Details of Plant Being Offered – 72.5 kV Current Transformers ................................................. 81

SCHEDULE 2 – Details of Plant Being Offered - 245 kV Current Transformers ................................................... 84

SCHEDULE 2 – Details of Plant Being Offered - 362 kV Current Transformers ................................................... 88

SCHEDULE 2 – Details of Plant Being Offered - 550 kV Current Transformers (1 Amp Secondary Cores) ......... 91

SCHEDULE 3: Information to be supplied by Respondents ................................................................................. 94

Schedule 4: Technical Requirements Compliance Schedule ............................................................................... 98

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1 PURPOSE
This document defines the performance and technical requirements for outdoor current
transformers (CT’s) for use on SP AusNet’s sub transmission and transmission networks.
This document is intended to cover the procurement of Current Transformers operating at
nominal system voltages of 22kV, 66kV, 220kV, 330kV and 500kV, and does not include
installation works.

2 REFERENCES

2.1 NATIONAL AND INTERNATIONAL STANDARDS

This Technical standard is based upon and refers to the following SP AusNet Technical
Standards, and National and International Standards.

Standard Reference Details

AS 60044.1 - 2007 Instrument Transformers – Part 1: Current Transformers.

AS 2650 - 2005 “Common specifications for high-voltage switchgear and control

gear standards (IEC 60694, Ed 2.2 (2002) MOD)”.

AS 1265 –1990 “Bushings for alternating voltages above 1000V (IEC 137 –
1984)”

AS 1767 – 1999 Insulating liquids – specification for unused mineral insulating

oils for transformers and switchgear

AS 2067-2008 “Switchgear assemblies and ancillary equipment for alternating

voltages above 1kV”.

AS 60270-2001 Partial Discharge Measurements

AS 2700 -1996 Colour Standards

AS 4100 – 1998 “Steel Structures”.

AS 4436 – 1996 Guide for the selection of insulators in respect of polluted

conditions

AS/NZS 4680 – 2006 “Hot dipped galvanized (zinc) coatings on fabricated ferrous
articles”

AS 62271.301 – 2005 “ High voltage switchgear and control gear Part 301 -
Dimensional standardisation of terminals”

IEC 60376 Ed 2 Specification of technical grade sulphur hexafluoride (SF6) for

use in electrical equipment

AS/NZS ISO 9001 Quality Management systems requirements

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2.2 SP AUSNET REFERENCE STANDARDS

• Station Design Manual -Steel Structures (Volume 5 –Section 22)

2.3 SP AUSNET REFERENCE DRAWINGS

The following drawings referred to in this Technical Standard will accompany and form
part of this Technical Standard:

Description Drawing Number

Typical Diagram Requirements for CT’s associated with 550, 362, 245
T14/159/ 363/1
and 72.5kV circuit breakers ( for Post type CT)
Typical Diagram Requirements for CT’s associated with 550, 362, 245
T14/159/ 363/ 2
and 72.5kV circuit breakers ( for Dead Tank CBs)
Standard Padlock – Outline Dimensions T14/316/32A

3 GENERAL REQUIREMENTS

3.1 DESCRIPTION
The following equipment is covered by this specification.

Item Description
No.
1 Three phase set of 24kV, 1600A, 31.5kA, Outdoor Current Transformers, complete
with Support Structures.
Each phase to consist of the following current transformer cores and ratios:
• Three Cores of Protection Current Transformers, each:
o 1500/1200/600/5A, Protection Class 0.15 PX 125 R0.6 on 1500/5A
ratio.
• One Core of Measurement Current Transformers:
o 1500/1200/600/5A, Class 0.5, 40VA

2 Three phase set of 24kV, 1250A, 31.5kA, Outdoor Current Transformers with the
following cores and ratios, complete with Support Structures if CT posts.
Each phase to consist of the following current transformer cores and ratios:
• Two Protection Cores as follows:
• One core 1500/1200/600/5A, Protection Class 0.15 PX 125 R0.6 on 1500/5A
ratio, and proportional performance on other ratios, and
• One core 1600/1200/900/5A, Protection Class 0.15 PX 130 R0.6 on 1600/5A
ratio and proportional performance on other ratios.
• One Core of Measurement Current Transformer as follows:
o 1200/600/400/5A, Class 0.5, 40VA on 1200/5, 600/5 and 400/5 Tap
ratios.

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3 Three phase set of 72.5kV, 2000A, 31.5kA, Outdoor Current Transformers, complete
with Support Structures.
Each phase to consist of the following current transformer cores and ratios:
• Four Cores of Protection Current Transformers, each:
o 2100/1600/1200/900/5A, Protection Class 0.14 PX 700 R1.1 on
2100/5A ratio.
• One Core of Protection-Measurement Current Transformer:
o 2100/1600/1200/900/5A, Protection Class 0.14 PX 700 R1.1 on
2100/5A ratio, and Measurement Class 0.5, 40VA.

4 Three phase set of 72.5kV, 3150A, 31.5kA, Outdoor Current Transformers, complete
with Support Structures.
Each phase to consist of the following current transformer cores and ratios:
• Four Cores of Protection Current Transformers, each:
o 3000/2100/1600/1200/5A, Protection Class 0.1 PX 1000 R1.6 on
3000/5A ratio.
• One Core of Protection-Measurement Current Transformer:
o 3000/2100/1600/1200/5A, Protection Class 0.1 PX 1000 R1.6 on
3000/5A ratio, and Measurement Class 0.5, 40VA.

5 Three phase set of 245kV, 3150A, 50kA, Outdoor Current Transformers, complete with
Support Structures.( With one metering core for standard applications – Metro and
regional stations)
Each phase to consist of the following current transformer cores and ratios:
• Four Cores of Protection Current Transformers, each:
o 3000/2100/1500/5A, Protection Class 0.1 PX 1200 R1.8 on 3000/5A
ratio.
• One Core Measurement Current Transformer:
o 3000/2000/1200/800/600/400/5A, Measurement Class 0.2, 40VA

6 Three phase set of 245kV, 3150A, 50kA, Outdoor Current Transformers, complete with
Support Structures. ( with two metering cores for revenue and check metering ,eg: YPS
Generator Circuits)
Each phase to consist of the following current transformer cores and ratios:
• Four Cores of Protection Current Transformers, each:
o 3000/2100/1500/5A, Protection Class 0.1 PX 1200 R1.8 on 3000/5A
ratio.
• Two Cores of Measurement Current Transformer:
o 3000/2000/1200/800/600/400/5A , Measurement Class 0.2, 40VA on
ratios.

7 Three phase set of 245kV, 4000A, 40kA, Outdoor Current Transformers, complete with
Support Structures.( with one metering core for special applications)
Each phase to consist of the following current transformer cores and ratios:
• Four Cores of Protection Current Transformers, each:
o 4000/3000/2100/1500/5A, Protection Class 0.075 PX 1600 R2.4 on

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4000/5A ratio.
• One Core Measurement Current Transformer:
3000/2000/1200/800/600/400/5A, Measurement Class 0.2, 40VA

8 Three phase set of 245kV, 3150A, 50kA, Outdoor Current Transformers, complete with
Support Structures. ( with 5A and 1.25A protection cores for HWPS only)
Each phase to consist of the following current transformer cores and ratios:
• Two Cores of Protection Current Transformers, each:
o 3000/2100/1500/5A, Protection Class 0.1 PX 1200 R1.8 on 3000/5A
ratio.
• Two cores of Protection Current Transformers, each:
o 2000/1.25A, Protection Class 1.25 PX 200 R2
• One Core Measurement Current Transformer:
o 3000/2000/1200/800/600/5A, Measurement Class 0.2, 40VA

9 Three phase set of 362kV, 3150A, 50kA, Outdoor Current Transformers, complete with
Support Structures.
Each phase to consist of the following current transformer cores and ratios:
• Four Cores of Protection Current Transformers, each:
o 3000/2000/1600/1200/1A, Protection Class 0.10 PX 3000 R6.0 on
3000/1A ratio.
• One Core Measurement Current Transformer:
o 3000/2000/1600/1200/800/600/1A, Measurement Class 0.2, 25VA
10 Three phase set of 550kV, 4000A, 63kA, Outdoor Current Transformers, complete with
Support Structures.
Each phase to consist of the following current transformer cores and ratios:
• Four Cores of Protection Current Transformers, each:
o 4000/3000/2500/1A, Protection Class 0.2 PX 5000 R10 on 4000/1A
ratio.
• One Core Measurement Current Transformer:
o 4000/3000/2000/1600/1200/800/600/1A, Measurement Class 0.2, 25VA

3.2 CLIMATIC CONDITIONS

The current transformers offered must be suitable for the following climatic conditions.

Climatic Condition Value

Maximum Solar Radiation 1.1kW/m2 on black surface. (equivalent to black body
temperature of + 80oC)

Maximum shade temperature Plus 50ºC.

Minimum temperature Minus 10ºC.

Maximum Temperature Change Up to 20ºC within a period of 20 minutes

Maximum wind velocity Steady Wind 110 km/h, Wind Gusts 160 km/h.
(Design wind velocity 34 m sec-1)

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Ice thickness <1 mm

Elevation <1000m.

Pollution Level Category III (Heavy) as per IEC 60815/AS4436

3.3 COMPLIANCE WITH NATIONAL ELECTRICITY RULES

In order to ensure satisfactory operation during normal and contingent system conditions, all
high voltage plant and equipment must withstand, without damage, and maintain adequate
performance under the system conditions specified in the National Electricity Rules- Certified
Initial Rules, Schedule 5.1a – System Standards.
A summary of the important aspects for switchgear equipment is listed below. These tables do
not replace the need to check and comply with the system conditions described in the National
Electricity Rules.
Where type tests do not cover the extremes of the system conditions, the expected capability
and performance at the extremes must be provided with supporting evidence.

Nominal System Minimum Maximum Earth fault factor

Voltage Continuous Continuous (voltage rise factor
(kV rms) Voltage Voltage during fault
(kV rms) (kV rms) clearance)
500 450 550 1.5
330 297 362 1.5
220 198 245 1.5

The 220 kV Current transformers must be suitable for use on a 220 kV system with a normal
system highest voltage of 245 kV. It should be noted that at some locations the 245 kV may be
exceeded, and the CT may be subjected to voltages up to 255 kV for periods normally no longer
than 30 minutes and for a total period of less than 1% per year.

Total harmonic voltage distortion 3%. The indicative harmonics and their voltage values are
shown in AS 61000.3.6(2001), Table 2.

Operating Frequency

Condition Range (Hz)

Normal operating frequency band 49.85 to 50.15
Extreme frequency excursion limits 47.0 to 52.0
(for up to 1 minute)

4 PERFORMANCE REQUIREMENTS
4.1 Minimum Performance Requirements

The Technical Schedules set out in this section provides details of the minimum performances
required for current transformers for items listed in section 3.1 of this technical standard.

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MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES, PROTECTION -
MEASUREMENT CORES, and MEASUREMENT CORES – 24kV, 31.5KA, 1600A, ITEM 1
• System Nominal Voltage 22kV rms
• System Highest Voltage 24kV rms
• Rated Frequency 50 Hz
• Rated Continuous Primary Current 1600A rms
• Rated Short Circuit: (3 Sec.) 31.5 kA rms
: (Peak Current) 79 kA peak
• Lightning Impulse Withstand Level 125 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 50 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 4.5 kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 3
Rated Transformation Ratio 1500/1200/600/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Protection Performance Secondary Continuous Rating of
Ratio (A) Classification Terminals Secondary Winding

1500/5A 0.15 PX 125 R0.6 S1-S4 7.5A

1200/5A 0.20 PX 100 R0.5 S1-S3 10A

900/5A 0.26 PX 75 R0.38 S2-S5 10A

600/5A 0.40 PX 50 R0.25 S1-S2 10A

300/5A 0.80 PX 25 R0.13 S3-S4 10A

2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 1500/1200/600/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Measuring Class Accuracy & Secondary Continuous Rating of
Ratio (A) Burden Rating Terminals Secondary Winding

1500/5A Cl. 0.5, 125% ext, 40VA, FS10 S1-S4 7.5A

1200/5A Cl. 0.5, 125% ext, 40VA, FS10 S1-S3 10A

600/5A Cl. 0.5, 125% ext, 40VA, FS10 S1-S2 10A

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MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES and
MEASUREMENT CORES – 24kV, 31.5KA, 1250A for 24 kV Capacitor Banks – Item 2
• Applicable Standard AS 60044.1 (2007)
• System Nominal Voltage 22kV rms
• System Highest Voltage 24kV rms
• Rated Frequency 50 Hz
• Rated Continuous Primary Current 1250A rms
• Rated Short Circuit: (1 Sec.) 31.5 kA rms
: (Peak Current) 85 kA peak
• Lightning Impulse Withstand Level 125 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 50 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms (Minimum)
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 4.5 kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts
1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES
Protection Core 1
Number of Cores per Phase 1
Rated Transformation Ratio 1500/1200/600/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Protection Secondary Continuous Rating of
Ratio (A) Performance Terminals Secondary Winding
Classification
1500/5A 0.15 PX 125 R0.6 S1-S4 7.5A
1200/5A 0.20 PX 100 R0.5 S1-S3 7.5A
900/5A 0.26 PX 75 R0.38 S2-S5 10A
600/5A 0.40 PX 50 R0.25 S1-S2 10A
300/5A 0.80 PX 25 R0.13 S3-S4 10A

Protection Core 2
Number of Cores per Phase 1
Rated Transformation Ratio 1600/1200/900/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Protection Secondary Continuous Rating of
Ratio (A) Performance Terminals Secondary Winding
Classification
1600/5A 0.15 PX 130 R0.6 S1-S4 7.5A
1200/5A 0.20 PX 100 R0.5 S1-S3 7.5A
900/5A 0.26 PX 75 R0.38 S1-S2 10A
700/5A 0.35 PX 60 R0.20 S2-S4 10A
400/5A 0.60 PX 35 R0.15 S3-S4 10A
300/5A 0.80 PX 25 R0.13 S2-S3 10A

Please Note! The Protection Performance Classification 0.15 PX 125 R0.6 represents the following
CT performance parameters: Ie PX Ek Rct, where:-
Ie is Maximum exciting current (Amps rms), at rated Knee point emf; PX is Class of CT; Ek is
Rated Knee point EMF (Volts rms); and Rct is maximum resistance of the secondary winding at a
temperature of 75°C, all on the rated turns ratio shown.

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2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores per Phase 1
Rated Transformation Ratio 1200/600/400/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Measuring Class Accuracy Secondary Continuous Rating of
Ratio (A) & Burden Rating Terminals Secondary Winding
1200/5 Cl. 0.5, 125% ext, 40VA, S1-S4 7.5A
600/5A Cl. 0.5, 125% ext, 40VA, S1-S4 10A
400/5A Cl. 0.5, 125% ext, 40VA, FS5 S1-S3 10A

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES, PROTECTION -

MEASUREMENT CORES, and MEASUREMENT CORES – 72.5kV, 31.5KA, 2000A, ITEM 3

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• System Nominal Voltage 66kV rms
• System Highest Voltage 72.5kV rms
• Rated Frequency 50 Hz
• Rated Continuous Primary Current 2000A rms
• Rated Short Circuit: (3 Sec.) 31.5 kA rms
: (Peak Current) 85 kA peak
• Lightning Impulse Withstand Level 325 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 140 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 7kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 4
Rated Transformation Ratio 2100/1600/1200/900/5A
Secondary Terminals S1-S2-S3-S4-25
Rated Transformation Protection Performance Secondary Continuous Rating of
Ratio (A) Classification Terminals Secondary Winding

2100/5A 0.14 PX 700 R1.1 S1-S5 7.5A

1600/5A 0.19 PX 530 R0.85 S1-S4 10A

1200/5A 0.25 PX 400 R0.64 S1-S3 10A

900/5A 0.33 PX 300 R0.48 S1-S2 10A

500/5A 0.60 PX 165 R0.26 S4-S5 10A

400/5A 0.75 PX 135 R0.21 S3-S4 10A

300/5A 1.00 PX 100 R0.16 S2-S3 10A

2. PERFORMANCE OF PROTECTION - MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 2100/1600/1200/900/5A
Secondary Terminals S1-S2-S3-S4-S5
Rated Protection Measuring Class Secondary Continuous Rating of
Transformation Performance Accuracy & Burden Terminals Secondary Winding
Ratio (A) Classification Rating

2100/5A 0.14 PX700 R1.1 Cl. 0.5, ext 125% 40VA S1-S5 7.5A

1600/5A 0.20 PX 530 R0.85 Cl. 0.5, ext 125% 40VA S1-S4 10A

1200/5A 0.26 PX 400 R0.64 Cl. 0.5, ext 125% 40VA S1-S3 10A

900/5A 0.36 PX 300 R0.48 Cl. 0.5, ext 125% 40VA S1-S2 10A

500/5A 0.60 PX 165 R0.26 Cl. 0.5, ext 125% 40VA S2-S4 10A

400/5A 0.80 PX 132 R0.21 Cl. 0.5, ext 125% 40VA S3-S4 10A

300/5 1.00 PX 100 R0.16 CL. 0.5 ext 125% 40VA S2-S3 10A

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES, PROTECTION -

MEASUREMENT CORES, and MEASUREMENT CORES – 72.5kV, 31.5KA, 3150A, ITEM 4

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• System Nominal Voltage 66kV rms
• System Highest Voltage 72.5kV rms
• Rated Frequency 50 Hz
• Rated Continuous Primary Current 3150A rms
• Rated Short Circuit: (3 Sec.) 31.5 kA rms
: (Peak Current) 85 kA peak
• Lightning Impulse Withstand Level 325 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 140 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 10kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 4
Rated Transformation Ratio 3000/2100/1600/1200/5A
Secondary Terminals S1-S2-S3-S4-S5

Rated Transformation Protection Performance Secondary Continuous Rating of

Ratio (A) Classification Terminals Secondary Winding

3000/5A 0.1 PX 1000 R1.6 S1-S5 7.5A

2100/5A 0.14 PX 700 R1.1 S1-S4 10A

1600/5A 0.19 PX 530 R0.85 S1-S3 10A

1200/5A 0.25 PX 400 R0.64 S1-S2 10A

900/5A 0.33 PX 300 R0.48 S1-S2 10A

500/5A 0.60 PX 165 R0.26 S4-S5 10A

400/5A 0.75 PX 135 R0.21 S3-S4 10A

300/5A 1.00 PX 100 R0.16 S2-S3 10A

2. PERFORMANCE OF PROTECTION - MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 3000/2100/1600/1200/5A

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Secondary Terminals S1-S2-S3-S4-S5
Rated Protection Performance Measuring Class Accuracy & Secondary Continuous
Transformati Classification Burden Rating Terminals Rating of
on Ratio (A) Secondary
Winding

3000/5A 0.1 PX1000 R1.6 Cl. 0.5, ext 125% 40VA, FS10 S1-S5 7.5A

2100/5A 0.14 PX700 R1.12 Cl. 0.5, ext 125% 40VA, FS10 S1-S4 10A

1800/5A 0.17 PX600 R0.96 Cl. 0.5, ext 125% 40VA, FS10 S2-S5 10A

1600/5A 0.19 PX 530 R0.85 Cl. 0.5, ext 125% 40VA, FS10 S1-S3 10A

1400/5A 0.21 PX 465 R0.75 Cl. 0.5, ext 125% 40VA, FS10 S3-S5 10A

1200/5A 0.25 PX 400 R0.64 Cl. 0.5, ext 125% 40VA, FS10 S1-S2 10A

900/5A 0.33 PX 300 R0.48 Cl. 0.5, ext 125% 40VA, FS10 S1-S2 10A

500/5A 0.60 PX 165 R0.26 Cl. 0.5, ext 125% 40VA, FS10 S2-S4 10A

400/5A 0.75 PX 135 R0.21 Cl. 0.5, ext 125% 40VA, FS10 S3-S4 10A

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES, PROTECTION -

MEASUREMENT CORES, and MEASUREMENT CORES – 245kV, 50KA, 3150A, ITEM 5
• System Nominal Voltage 220kV rms
• System Highest Voltage 245kV rms

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• Rated Frequency 50 Hz
• Rated Continuous Primary Current 3150A rms
• Rated Short Circuit: (1 Sec.) 50 kA rms
: (Peak Current) 135 kA peak
• Lightning Impulse Withstand Level 1050 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 460 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 10kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 4
Rated Transformation Ratio 3000/2100/1500/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Protection Performance Secondary Continuous Rating of
Ratio (A) Classification Terminals Secondary Winding

3000/5A 0.10 PX 1200 R1.8 S1-S4 7.5A

2100/5A 0.14 PX 840 R1.3 S1-S3 10A

1500/5A 0.20 PX 600 R0.9 S1-S2 & S2-S5 10A

900/5A 0.33 PX 360 R0.54 S3-S4 10A

600/5A 0.50 PX 240 R0.6 S2-S3 10A

2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 3000/2000/1200/800/600/400/5A
Secondary Terminals S1-S2-S3-S4-S5
Rated Transformation Measuring Class Accuracy & Secondary Continuous Rating of
Ratio (A) Burden Rating Terminals Secondary Winding

3000/5A Cl. 0.2, 125% ext, 40VA, S1-S7 7.5A

FS10

2000/5A Cl. 0.2, 125% ext, 40VA, S1-S6 10A

FS10

1200/5A Cl. 0.2, 125% ext, 40VA, S1-S5 10A

FS10

800/5A Cl. 0.2, 125% ext, 40VA, S1-S4 10A

FS10

600/5A Cl. 0.2, 125% ext, 40VA, S1-S3 10A

FS10

400/5A Cl. 0.2, 125% ext, 40VA, S1-S2 10A

FS10

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES, PROTECTION -

MEASUREMENT CORES, and MEASUREMENT CORES – 245kV, 50KA, 3150A, ITEM 6
• System Nominal Voltage 220kV rms
• System Highest Voltage 245kV rms

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• Rated Frequency 50 Hz
• Rated Continuous Primary Current 3150A rms
• Rated Short Circuit: (1 Sec.) 50 kA rms
: (Peak Current) 135 kA peak
• Lightning Impulse Withstand Level 1050 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 460 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 10kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 4
Rated Transformation Ratio 3000/2100/1500/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Protection Performance Secondary Continuous Rating of
Ratio (A) Classification Terminals Secondary Winding

3000/5A 0.10 PX 1200 R1.8 S1-S4 7.5A

2100/5A 0.14 PX 840 R1.3 S1-S3 10A

1500/5A 0.20 PX 600 R0.9 S1-S2 & S2-S5 10A

900/5A 0.33 PX 360 R0.54 S3-S4 10A

600/5A 0.50 PX 240 R0.6 S2-S3 10A

2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 2
Rated Transformation Ratio 3000/2000/1200/800/600/400/5A
Secondary Terminals S1-S2-S3-S4-S5
Rated Transformation Measuring Class Accuracy & Secondary Continuous Rating of
Ratio Burden Rating Terminals Secondary Winding

3000/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S7 7.5A

2000/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S6 10A

1200/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S5 10A

800/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S4 10A

600/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S3 10A

400/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S2 10A

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES and MEASUREMENT

CORES – 245kV, 40KA, 4000A, ITEM 7
• System Nominal Voltage 220kV rms
• System Highest Voltage 245kV rms

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Outdoor Current Transformers –Equipment Specification

• Rated Frequency 50 Hz
• Rated Continuous Primary Current 4000A rms
• Rated Short Circuit: (1 Sec.) 40 kA rms
: (Peak Current) 108 kA peak
• Lightning Impulse Withstand Level 1050 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 460 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 10kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 4
Rated Transformation Ratio 4000/3000/2100/1500/5A
Secondary Terminals S1-S2-S3-S4-S5

Rated Transformation Protection Performance Secondary Continuous Rating of

Ratio (A) Classification Terminals Secondary Winding

4000/5A 0.075 PX 1600 R2.4 S1-S5 7.5A

3000/5A 0.10 PX 1200 R1.8 S1-S4 10A

2500/5A 0.12 PX1000 R1.5 S2-S5 10A

2100/5A 0.14 PX840 R1.3 S1-S3 10A

1900/5A 0.157 PX760 R1.15 S3-S5 10A

1500/5A 0.20 PX600 R0.9 S1-S2 & S2-S4 10A

1000/5A 0.30 PX 400 R0.6 S4-S5 10A

900/5A 0.33 PX360 R0.54 S3-S4 10A

600/5A 0.50 PX 240 R0.6 S2-S3 10A

2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 4000/3000/2000/1200/800/600/400/5A

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Secondary Terminals S1-S2-S3-S4-S5-S6-S7-S8

Rated Transformation Measuring Class Accuracy & Secondary Continuous Rating of

Ratio (A) Burden Rating Terminals Secondary Winding

4000/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S8 7.5A

3000/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S7 10A

2000/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S6 10A

1200/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S5 10A

800/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S4 10A

600/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S3 10A

400/5A Cl. 0.5, 125% ext, 40VA, FS10 S1-S2 10A

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES, PROTECTION -

MEASUREMENT CORES, and MEASUREMENT CORES – 245kV, 50KA, 3150A, ITEM 8
• System Nominal Voltage 220kV rms
• System Highest Voltage 245kV rms

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Outdoor Current Transformers –Equipment Specification

• Rated Frequency 50 Hz
• Rated Continuous Primary Current 3150A rms
• Rated Short Circuit: (1 Sec.) 50 kA rms
: (Peak Current) 135 kA peak
• Lightning Impulse Withstand Level 1050 kV peak
• 50 Hz Withstand Voltage (1 Min., wet and dry) 460 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 3 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 10kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 2+2
Rated Transformation Ratio (2 Cores – Source or Bus Side) 3000/2100/1500/5A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Ratio (2 Cores – Load Side) 2000/1.25A
Secondary Terminals S1-S2

Rated Transformation Protection Performance Secondary Terminals Continuous Rating

Ratio (A) Classification of Secondary
Winding

Source or Bus
Side
3000/5A 0.10 PX 1200 R1.8 S1-S4 7.5A

2100/5A 0.14 PX 840 R1.3 S1-S3 10A

1500/5A 0.20 PX 600 R0.9 S1-S2 & S2-S5 10A
900/5A 0.33 PX 360 R0.54 S3-S4 10A
600/5A 0.50 PX 240 R0.6 S2-S3 10A

Load Side

2000/1.25A 1.25 PX 200 R2 S1-S2 2.5A

2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 3000/2000/1200/800/600/5A
Secondary Terminals S1-S2-S3-S4-S5-S6

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Rated Transformation Ratio Measuring Class Accuracy & Secondary Continuous Rating
Burden Rating Terminals of Secondary
Winding

3000/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S6 7.5A

2000/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S5 10A

1200/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S4 10A

800/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S3 10A

600/5A Cl. 0.2, 125% ext, 40VA, FS10 S1-S2 10A

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES and MEASUREMENT

CORES – 362kV, 50KA, 3150A, ITEM 9
• System Nominal Voltage 330kV rms
• System Highest Voltage 362kV rms

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Outdoor Current Transformers –Equipment Specification

• Rated Frequency 50 Hz
• Rated Continuous Primary Current 3150A rms
• Rated Short Circuit: (1 Sec.) 50 kA rms
: (Peak Current) 125 kA peak
• Lightning Impulse Withstand Level 1300 kV peak
• Switching Impulse Withstand Level (to Earth) 950 kV rms
• 50 Hz Withstand Voltage (1 Min., wet and dry) 520 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 5 kV rms Secondary
Winding Rated Inter-turn Withstand Voltage (1 min.) 10 kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 4
Rated Transformation Ratio 3000/2000/1600/1200/1A
Secondary Terminals S1-S2-S3-S4-S5

Rated Transformation Protection Performance Secondary Continuous Rating of

Ratio (A) Classification Terminals Secondary Winding

3000/1A 0.10 PX 3000 R5 S1-S5 2.5A

2000/1A 0.15 PX 2000 R3.35 S1-S4 2.5A

1800/1A 0.17 PX 1800 R3.0 S2-S5 2.5A

1600/1A 0.19 PX 1600 R2.7 S1-S3 2.5A

1400/1A 0.23 PX 1400 R2.35 S3-S5 2.5A

1200/1A 0.25 PX 1200 R2.0 S1-S2 2.5A

1000/1A 0.30 PX 1000 R1.65 S4-S5 2.5A

800/1A 0.38 PX 800 R1.35 S3-S4 2.5A

400/1A 0.75 PX 400 R0.65 S2-S3 &S-S4 2.5A

2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 3000/2000/1600/1200/800/600/1A
Secondary Terminals S1-S2-S3-S4-S5-S6-S7

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Rated Transformation Measuring Class Accuracy & Secondary Continuous Rating of

Ratio (A) Burden Rating Terminals Secondary Winding

3000/1A Cl. 0.2, 125% ext, 40VA, FS10 S1-S7 2.5A

2000/1A Cl. 0.2, 125% ext, 40VA, FS10 S1-S6 2.5A

1600/1A Cl. 0.2, 125% ext, 40VA, FS10 S1-S5 2.5A

1200/1A Cl. 0.2, 125% ext, 40VA, FS10 S1-S4 2.5A

800/1A Cl. 0.2, 125% ext, 40VA, FS10 S1-S3 2.5A

600/1A Cl. 0.2, 125% ext, 40VA, FS10 S1-S2 2.5A

MINIMUM PERFORMANCE REQUIREMENTS OF PROTECTION CORES and MEASUREMENT

CORES – 550kV, 63KA, 4000A, ITEM 10
• System Nominal Voltage 500kV rms
• System Highest Voltage 550kV rms
• Rated Frequency 50 Hz

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• Rated Continuous Primary Current 4000A rms
• Rated Short Circuit: (1 Sec.) 63 kA rms
: (Peak Current) 170 kA peak
• Lightning Impulse Withstand Level 1550 kV peak
• Switching Impulse Withstand Level (to Earth) 1175 kV rms
• 50 Hz Withstand Voltage (1 Min., wet and dry) 680 kV rms
• Secondary Winding Rated Insulation Withstand Voltage (1min.) 5 kV rms
• Secondary Winding Rated Inter-turn Withstand Voltage (1 min.) 10 kV peak
• Maximum internal partial Discharge at 120% maximum continuous
Phase to Earth voltage <5 pC
• Radio Interference voltage <500 microvolts

1. PERFORMANCE OF PROTECTION CURRENT TRANSFORMER CORES

Number of Cores 4
Rated Transformation Ratio 4000/3000/2500/1A
Secondary Terminals S1-S2-S3-S4
Rated Transformation Protection Performance Secondary Continuous Rating of
Ratio (A) Classification Terminals Secondary Winding

4000/1A 0.20 PX 5000 R10 S1-S4 2.5A

3000/1A 0.27 PX 3750 R7.5 S1-S3 2.5A

2500/1A 0.32 PX 3125 R6.25 S2-S2 2.5A

1500/1A 0.53 PX 1875 R3.75 S2-S4 2.5A

1000/1A 0.80 PX 1250 R2.35 S3-S4 2.5A

500/1A 1.60 PX 625 R1.25 S2-S3 2.5A

2. PERFORMANCE OF MEASUREMENT CURRENT TRANSFORMER CORES

Number of Cores 1
Rated Transformation Ratio 4000/3000/2000/1600/1200/800/600/1A
Secondary Terminals S1-S2-S3-S4-S5-S6-S7-S8
Rated Transformation Measuring Class Accuracy & Secondary Continuous Rating of
Ratio (A) Burden Rating Terminals Secondary Winding

4000/1A Cl. 0.2, 125% ext, 25VA, FS10 S1-S8 2.5A

3000/1A Cl. 0.2, 125% ext, 25VA, FS10 S1-S7 2.5A

2000/1A Cl. 0.2, 125% ext, 25VA, FS10 S1-S6 2.5A

1600/1A Cl. 0.2, 125% ext, 25VA, FS10 S1-S5 2.5A

1200/1A Cl. 0.2, 125% ext, 25VA, FS10 S1-S4 2.5A

800/1A Cl. 0.2, 125% ext, 25VA, FS10 S1-S3 2.5A

600/1A Cl. 0.2, 125% ext, 25VA, FS10 S1-S2 2.5A

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Outdoor Current Transformers –Equipment Specification

5 TECHNICAL REQUIREMENTS

5.1 General Current Transformer Requirements

The current transformers will be connected to an effectively earthed, 50 Hz, three phase system
and must be capable of satisfactory continuous operation up to the system highest voltage
specified.
Post type current transformers must be of the outdoor, single-phase type. Tenderers may offer
either oil based or SF6 insulated current transformers. Each complete unit must be suitable for
mounting on a structure.
The design of the current transformer must be such that different parts of the insulation are
properly coordinated, so that if the current transformer is subjected to an impulse voltage higher
than the specified withstand value, breakdown of the line-to-ground insulation may occur, but
only externally in air. The internal distribution of voltage within the weather shield insulator must
be approximately the same as the external resistive distribution so that pollution performance is
adequate.
Each post must contain the number and type of protection and metering current transformer core
units specified in the Table of Required Performance and Drawing T14/159/363/1.
Protection current transformers must be low leakage reactance design on all available ratios, in
accordance with Section 14.3.1 of AS 60044.1-2007, with the exception that current transformer
cores must be built of continuous rolled strip and must NOT contain any design air gaps to
modify their transient performance or remanence flux in the core.
As SP AusNet may utilise any of the nominated taps, the low leakage reactance design is
required for ALL the ratios shown in the minimum performance requirements.
Where the current transformers are ring type incorporated over the bushings of a dead tank
circuit breaker, the cores may be divided into two groups as shown in T14/159/363/2.
Current transformers must not have primary winding tappings.
Current Transformers offered must be suitable for a life of at least 45 years in service.

5.1.1 Insulator Housing

The insulator housing of current transformers shall be high temperature vulcanised (HTV)
silicone rubber composite material with silicone content >35%.. The type of housing shall be
nominated by the Tenderer. The colour of the polymer enclosures must be a light blue-grey or
light grey to AS 2700 (B44 or N22 or equivalent).
Consideration will be given for epoxy resin type for 24kV current transformers must be at the
sole discretion of the SP AusNet.

5.1.2 Creepage Distance

Insulators must be suitable for class III Heavy pollution conditions, as per IEC 60815
requirements. Minimum specific creepage distance must be 25mm/kV, based upon rated line-
to-line voltage.

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5.1.3 Terminals
5.1.3.1 Primary Terminal
The high voltage terminal of all current transformers must be a flat aluminium alloy palm terminal
or tinned / silver copper terminal in accordance with AS 62271.301 – 2005 as follows:

Normal current rating Terminal Number

1250A 5
2000A 8
3150A 9

4000A 10

5.1.3.2 Current Transformer Head Cover Bonding

Facilities must be provided that bond the current transformer head cover to the primary terminal
that has been labelled P1 for polarity purposes. The preferred arrangement is for a suitable link
between the current transformer cap and the primary terminal P1.
5.1.3.3 Maximum Forces Permitted on Primary Terminals
Supplier must advise the recommended static and dynamic mechanical terminal loads on
current transformer terminals that will be permitted so as not to exceed stresses resulting from
wind and fault withstand.
5.1.3.4 Secondary Terminals and Wiring Connections
All taps on the secondary windings must be brought out to terminals in a weatherproof terminal
box mounted on the current transformers. The arrangement adopted for the secondary terminals
of the current transformers must conform to the wiring diagram supplied with the plant, and must
be logical and consistent. The secondary terminals must be located and mounted in the
secondary terminal box and their markings must conform to the tap markings shown in Drawing
No. T14/159/363/1 & /2, for each current transformer in the post or bushing.
Secondary terminals must preferably be of the single stud type of brass material of not less than
6 mm diameter, or stainless steel of not less than 4.5 mm diameter, with all barriers between
adjacent studs spaced with a minimum of 20 mm clear gap between the barriers.
Where moulded type terminal strip assemblies are provided for connection of external wiring the
components must be assembled as follows:
Nut (run up to base of terminal stud)
Link if applicable
Secondary connections (Ross Courtney or Compression Lug)
Washer
Nut.
If tunnel type terminal units are used to provide an interface to external wiring, they must be
Phoenix UK10 or equivalent.
All secondary terminal assemblies mounted in the current transformer tank wall must provide
sealing against oil or SF6 leakage. The number of separable parts and sealing face length
should be minimised and seals must preferably be ‘O’ rings in groves sealing against machined
faces. Sealing design should be advised.

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Outdoor Current Transformers –Equipment Specification

5.2 CONSTRUCTION

5.2.1 Quality

HTV Silicone Polymer insulation must not rely on adhesives for joints in tension. Flange joints
must be designed to minimise the retention of water in contact with the edge of any gaskets.
For 24kV current transformers, epoxy cast resin insulation may be considered and it shall be of
proven cycloaliphatic epoxy resin material suitable for use in heavily polluted outdoor
environments.
Post current transformers, with a hairpin primary arrangement, must have the insulated primary
hairpin supported at the lower end and must not rely on the connection terminals for support.
Post current transformers, with a straight bar primary arrangement, must be adequately
designed for supporting the weight of cores. Insulating bushing material surrounding a primary
terminal must not deteriorate in service.
Oil filled current transformers must be designed so that in the event of an internal fault, pressure
is relieved and the insulator will not fail explosively.
SF6 insulated current transformers must be fitted with an effective method of pressure relief.
SF6 leakage must be guaranteed better than 0.5% per year.
All current transformers must be built to accurate dimensions and all holes must be jig drilled so
that any current transformer or current transformer component is interchangeable with another
from the same order.
Flanges on enclosures must be designed to have water-shedding covers to prevent water from
remaining in contact with the upper surface of the seal.
5.2.2 Bolts
Stainless steel bolts, nuts and washers must be provided in situations where electrolytic
corrosion may occur. The choice of stainless steel must be such that nuts and bolts must not be
the same alloy so that they will not ‘freeze’ when being tightened or undone.
Non-ferrous bolts must not be used under any circumstances except with the express
permission of SP AusNet.
5.2.3 Locking
Split spring washers, star washers, and other similar types of locking washers must not be used.
Locking plates of soft steel non-corrosive finish or brass must be used instead. All bolted and
screwed assemblies located inside the current transformer must be locked by locking plates,
locknuts, welding, wiring, punching or other approved means.
5.2.4 Insulating Liquid
The Tender must state what dielectric liquid is used in the CTs. If oil is used, the brand, grade
(inhibited or non-inhibited) dielectric strength, dielectric dissipation factor, acidity, flashpoint,
viscosity and resistivity must be stated. If any other dielectric is proposed, a full and detailed
description, including composition, flammability and toxicity, must be supplied.
Tenderers must provide a Material Safety Data Sheet and Material Technical Data Sheet for the
dielectric liquid that will be used in the CTs.
Wherever the word “oil” appears in relation to a dielectric in this Technical Standard and the
annexed schedules, it must be deemed to include any other liquid dielectric that may be
supplied.

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Outdoor Current Transformers –Equipment Specification

5.2.5 Oil sampling and filling

Provision shall be made in oil filled post type current transformers for sampling for condition
monitoring and filling. Clear instructions in the maintenance manual shall be provided for taking
samples for DGA analysis. Sampling valve shall be offered.
5.2.6 Oil Level and Nitrogen Pressure Indicators
Oil filled current transformers must have an oil level indicator in bellows type construction, or a
nitrogen pressure indicator in nitrogen-cushion type construction. It must be possible to read
indicators while standing on the ground. Any current transformers with nitrogen cushions must
preferably have oil levels above any sealing points.
It must be possible to recharge the nitrogen space without passing nitrogen past paper
insulation.
5.2.7 SF6 Density Monitors
SF6 filled current transformers must have a gas density monitor. The gas density monitor must
have local visual indication that must be easily read while standing at ground level.
The monitor must also provide at least three alarm levels, namely an over-pressure alarm to
permit auto-de-energisation, a low pressure alarm for gas topping while full insulation capability
is retained, and a low pressure trip setting for auto-de-energisation or introduction to remove
from service.
In addition a transducer that provides a 4 – 20 mA analogue output to represent gas density, for
use in condition monitoring system is to be offered.
It must be possible to replenish SF6 gas from ground level without infringing safety clearance
distances to live parts. The filling pint must be within 2m of ground level. The replenishment of
SF6 must not require the removal or disconnection of density monitor switches.
The density monitor must be able to be removed safely for calibration checks without removing
gas from CT. Instructions for removal or in situ calibration checks must be included in the
maintenance instructions.
5.2.8 Solid Insulating material
For 24kV, option for supply of cast epoxy resin current transformers may be considered. Full
detailed description, including composition, product processing, mechanical and physical
properties, flammability, insulation class and toxicity of the material must be supplied.
Consideration of epoxy resin will be at the sole discretion of SP AusNet.
5.2.9 Painting and Preservation
The current transformer must be supplied in a form where they can be stored outdoors for a
considerable time before use. Any points of water entry to vulnerable areas must be sealed
against water ingress or corrosion. In the event that the current transformer is supplied in a
horizontal position but it must be un-crated and stood vertically for long-term storage, this must
be advised at time of tender.
Oil insulated post current transformers must be supplied filled with new oil complying with AS
1767 - 1969. The units must be supplied fully filled.
SF6 insulated current transformers must be supplied filled with new SF6 to a pressure
acceptable for transportation but not less than 50 kPa. The SF6 must comply with IEC 60376 for
new gas. If current transformers are supplied with a reduced pressure, a sticker must be
attached to the unit warning that the gas pressure must be increased to the specified value
before the unit is placed in service. Unless otherwise negotiated the supplier must supply
sufficient new SF6 in internally clean cylinders to fully pressurise all current transformers
supplied on the order.

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Current transformers must be capable of withstanding normal erection stresses and must be
capable of being transported in a fully assembled state on Australian roads without requiring
additional and/or special packing.
Parts exposed to the weather must not rely on painting for preservation. Parts must be
constructed of either relatively non-corrosive materials such as aluminium or stainless steel or, if
steel, must be hot dip galvanized to AS 4680. Except for thin sheet, the zinc galvanizing must
not be less than 600 gm/m2. Painting or powder coating of steel as the sole external protection
is NOT acceptable. If paint is used it must only be to unify the appearance of the device and
must not be required for preservation. Paint colour must be neutral grey or light grey-blue (N23
or B44 to AS 2700 – 1996). For surfaces that are normally above earth potential and require
painting in accordance with standard practice, the finishing coat must be rust inhibiting
aluminium. Painting is not required for identifying high voltage components or the phase to
which the voltage transformer is connected.
Any internal surfaces in contact with oil must be scrupulously clean prior to filling and treated to
inhibit any action between the oil or liquid dielectric and its enclosure. Internal treatment of tanks
and enclosures is negotiable but must be such that there is no contamination of the oil or SF6.
All machined surfaces, left bare, must be coated with some easily removable compound that will
protect them from corrosion during transport and during storage.
Where there are exposed bolted connections they must be so designed and sealed that the risk
of water entry is minimal. Bolt threads must not project upwards from top surfaces unless the
bolt thread is completely sealed by cap nuts and soft metal washers. Paint or sealing
compounds must not be relied upon for water sealing but may be used to improve the
effectiveness of other seals.
Flanges on enclosures must be designed to have water-shedding covers to prevent water from
remaining in contact with the upper surface of the seal.
5.2.10 Special Environmental: Toxicology Safety
The Tenderer shall provide full details, including composition and toxicological information,
regarding the health and safety aspects of the materials offered in their products that are known
to have risks to health or the environment.
Recommended procedures shall be provided for the safe handling, safe operation and
maintenance of products supplied. The means of disposal of the materials shall be stated.
Material safety data sheets shall be provided, with copies available on site, for materials that are
supplied and subject to safety considerations in handling and use.

5.2.11 Secondary Windings design

The secondary windings must be capable of withstanding full rated fault current through the
primary conductor on any tap including the intermediate taps shown in the Table of Required
Performance.
For metering current transformers the fault withstand capability on all taps nominated for use is
required similar to the rated fault withstand capability for the protection current transformers.
The use of different gauge winding conductors or parallel conductors to meet the secondary
winding fault withstand is not precluded but the winding distribution around the toroid should be
as even as practicable. Where different gauges of winding conductor are used the tenderer must
state this in his offer, and must show the resistance of the winding between each nominated tap
in the guaranteed performance schedules.

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5.2.12 Protective Devices to Prevent Secondary Windings Flashover

Where the withstand capability of the secondary winding to open-circuit secondary voltage is
limited, it is preferred that a protective device is fitted to ensure the integrity of the plant is not
threatened by internal flashovers.
The design of the protective devices must be such that they must not operate or affect
performance of the current transformer below the peak knee- point voltage of the CT and it must
not operate or affect the performance of the current transformer below the Secondary Winding
Rated withstand level for Inter-turn Insulation shown in the Table of Required Performance.
The operation of the protective device must not endanger the integrity of the Equipment. The
flashover voltage of the secondary terminals, with the protective devices removed, must exceed
the operating voltage of the protective devices to ensure proper insulation grading, i.e., the
protective device operates also to protect the secondary terminals from flashing over and
damaging the CT.
Protective devices preferably must be capable of continuous operation to protect against
undetected open circuits. If devices have only a short term rating, without changing their
characteristics in an adverse way, the time for which the device may be relied upon must be
stated.
If Tenderers wish to offer different protective devices, they must submit details of the method of
protection proposed to SP AusNet.
5.2.13 Polarities
The polarity of the current transformers must be arranged so that current flow into primary
terminal P1 induces current flow out of secondary terminal S1 at the same instant.
For post type current transformers, the polarity markings must be in accordance with
AS 60044.1 – 2007, and must be as shown on Drawing No. T14/159/363/1.
For bushing type current transformers, the polarity markings must be in accordance with
AS 60044.1 – 2007, and must be as shown on Drawing No. T14/159/363/2.
It is preferred that all metering current transformer ratios specified in the”Table of Required
Performances” be achieved using the same terminal for the polarity end of the secondary
winding. The use of an intermediate terminal for the polarity end of a section of the secondary
winding to achieve one or more of the lower ratios required may be acceptable provided that the
ratios achieved in this manner fully conform to specified accuracy and other requirements. The
secondary terminals to be used for ratios achieved in this manner must be nominated in the
information shown on the rating plate. Tests must be carried out on all specified ratios to prove
compliance with this specification.

5.2.14 Support Structures

If supplied, support structure must be constructed of galvanised steel, designed to meet all
requirements of AS 4680, AS 4100 and to meet the design requirements of steel structures as
per section 22 of volume 5 of Station Design Manual of SP AusNet.

Structure heights required for circuit breakers shall be as follows:

• Structures for 24kV and 72.5kV current transformers must ensure that the lowest external
insulation is located not less than 2450 mm above the finished ground level.

• The overall height of the 245kV current transformers assembly including the support
structure required shall be 6250 mm from the base of the assembly to the centreline top of
the current transformer palm in order to provide maintenance vehicle access.

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• For 362kV and 500kV, higher structure height may be required depending on the height of
lowest external insulation of current transformer offered in order to provide a line terminal
height of not less than 7.8m and 9.0m respectively.

Structures must be of adequate strength and adequately braced to withstand the concurrent
loadings imposed by the operation of the plant, the weight of plant and busbars and winds of up
to 48m/s and be in accordance with AS4100 - 1998. Structures must also be adequate for
loads imposed by fault currents and wind speeds of 34m/s.

5.2.15 Marshalling Boxes

Marshalling boxes and Cubicles must be of minimum 3 mm thick aluminium or 2 mm thick hot
dip galvanised steel plate, or 1.6 mm thick stainless steel. Powder coated, non-galvanised steel
cubicles are not acceptable. Degree of protection for the cubicle must be IP55 or higher.

5.3 Terminating boxes, Connections and Terminal Markings

5.3.1 Terminating boxes

The secondary connections of post type current transformers will be brought out by SP AusNet
by wiring to terminal boards or terminal strips which must be located in the associated current
transformer marshalling box, where the marshalling box is part of the equipment to be supplied
by the current transformer supplier. Connections and terminal arrangements must be in
accordance with the Clause 8.2, “Secondary Terminals and Wiring Connections” and Drawing
No. T14/159/363/1.
If the current transformers are ring type, installed over bushings of a dead tank circuit breaker,
the terminal boards or terminal strips must be provided and mounted either in the main control
cabinet of the circuit breaker, or in a separate current transformer marshalling box, where the
marshalling box is part of the equipment to be supplied by the equipment supplier.
The terminal units in the main control cabinets and marshalling boxes must be Phoenix UK10 or
equivalent suitable for cables from 2.5 mm² to 10 mm². The terminal strips may be mounted
vertically or horizontally, and must be arranged with a minimum segregation of 100 mm between
individual CT terminal groups or segregated with insulating barriers.
The Connections and terminal arrangements in the main control cabinets and marshalling boxes
must be in accordance with Drawing No. T14/159/363/1 & /2.

5.3.2 Marking of terminals

The terminals on both primary and secondary sides of each current transformer must be clearly
and indelibly marked in accordance with the requirements of AS 60044.1.

5.4 Earthing
All metal parts of the equipment which are at earth potential must be jointed or bonded so that
they can be effectively earthed to an appropriate earthing terminal point that will be provided by
SP AusNet.
A copper earthing bar of approved dimensions must be provided in each current transformer
marshalling box.

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One earthing point must be provided on each separate post current transformer and on the
earthing bar in each marshalling box. Each earthing terminal point must consist of two 14 mm
diameter bolt holes 40 mm apart, or equivalent facility, for connecting to 50 mm x 6 mm copper
bar earthing conductors by means of two 12 mm diameter galvanised steel bolts spaced at 40
mm centres. The support structure must have two diametrically opposed earthing points at its
base, each with two 14 mm diameter bolt holes 40 mm apart.
5.5 Rating Plates
Each current transformer group must be provided with a brass or stainless steel rating plate
which will remain legible for the life of the current transformer on which must be etched the
information required by AS 60044-1 - 2007, and also the following information:
For Post type Current Transformers-
A schematic diagram of the primary and secondary windings in the order in which they are
located on the primary winding, including the terminal markings on the primary and secondary
windings, as shown in Drawing T14/159/363/1.
The rating plate must be mounted parallel to an imaginary line drawn between primary terminals
P1 to P2, with the P1 Terminal of the Rating Plate at the same end of the current transformer as
the primary terminal P1.
For Bushing type Current Transformers (incorporated in dead tank circuit breakers) -
A schematic diagram of the Primary and Secondary windings in the order in which they are
located on the primary winding, including the terminal markings on the primary and secondary
windings, as shown in Drawing T14/159/363/2, for the current transformers in the bushing, for
each bushing.
Each rating plate must be mounted parallel to an imaginary line drawn between primary
terminals P1 to P2, with the P1 terminal of each Rating Plate at the same end of the current
transformer as the primary terminal P1 in the bushing to which the rating plate applies.
Information pertaining to the current transformer cores, including:
1) The Number of the Australian Standard and date (AS 60044.1 – 2007)
2) Core No.;
3) Transformation ratios shown in the Table of Required Performance;
4) Secondary tapping terminal markings for each core;
5) The Class of current transformers; and the associated ratios on which the class is
based. For Class PX current transformers, this must include Ek, Ie, and Rct values applicable,
at the maximum rated Ratio of the CT.
For the latter SP AusNet’s preferred way of showing this information on the Rating Plate is the
designation described in the previous Australian Standard, AS 1675-1986, which shows in one
line the following, in the sequence stated here:
Maximum Ie (in amperes) at the rated Ek, Class (PX), rated Ek voltage, Letter R (for
Resistance), and maximum Rct at 75 ºC.
For example a 3000/2100/1500/5 245 kV CT with rated Ek 1200 volts, and corresponding Ie of
0.1 Amps, and Rct of 1.8 ohms , all on 3000/5 ratio, should be shown as:
0.1PX1200 R1.8

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5) Metering Current Transformers, the Class and associated ratios on which the Class is
based. For example a metering CT with 0.5 accuracy classification, and
3000/2000/1200/800/400/5 and 40 VA Rated output on each ratio, should be shown as:
0.5M (M to indicate metering), for each ratio at which this classification applies.
All rating plates must be capable of being read by a person standing on the ground or any
walkway or platform provided as part of the plant.

5.6 TESTING

5.6.1 General

Tests must be carried out in accordance with AS 60044.1-2007 or as required by this Technical
Standard.
The Submission of complete information is a necessary preliminary to the acceptance by SP
AusNet of any Tender. The submission of type tests in an electronic form is acceptable but it is
preferred that type tests are submitted in a form such that they cannot be accidentally altered or
corrupted.

5.6.2 Test Information to Accompany Tender

Tenderers must submit with their Tenders, test sheets, oscillograms and other data, certified by
a Testing authority approved by SP AusNet, establishing that each item of plant offered has the
performance guaranteed by them in Guaranteed Performance schedules, and that a complete
unit of each type offered has passed all type tests specified.
If no comment be made in the Tender with respect to the performance of type and/or routine
tests it is mandatory that the Supplier perform and submit results of all such tests without
charge.
Where incomplete type test data is submitted and no statement is made by the Tenderer
expressing his agreement to have the necessary tests performed, the Tender is liable to
rejection.

5.6.3 TESTING BY SUPPLIER BEFORE DELIVERY

The Supplier must carry out tests during manufacture of the plant as provided for in the Contract
conditions and this Technical Standard to prove compliance with the minimum performance
requirements stated in Section 4.1.
Where the Supplier considers that type tests previously performed meet the requirements of a
particular test specified in this Technical Standard, if they have not already been submitted, full
details of such tests including complete test results certified by a recognised testing laboratory
must be submitted for consideration by SP AusNet who may accept such test in lieu of further
testing.
SP AusNet or its representative may be present at all tests, and the Supplier must give
reasonable notice in writing, before such tests are carried out. Within a period of four weeks
after the completion of any test, the Supplier must forward to SP AusNet certified test sheets in
triplicate showing the results of such test.

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5.7 TYPE TESTS

5.7.1 General

All guaranteed performance values must be supported by type test data. Tests must be carried
out in accordance with AS60044.1 - 2007 and this Technical Standard. Where the Technical
Standard differs from AS60044.1 – 2007 the requirements of the Technical Standard must
prevail. The type test index schedule lists out the standard tests that must be successfully
performed and completed, (Refer to Appendices).
Where type test data does not exist for the item offered, test on equivalent items will be
considered only if details of similarities and differences and a justification of relevant equivalence
for equipment and test layout are provided.
The type tests indicated below must be performed in addition to the mandatory tests included in
AS 60044.1-(2007).

5.7.2 Standard Type Tests

Standard type tests as listed in AS 60044.1-2007 to be carried out are listed below.

1. Short Time & Peak Current Withstand Test

2. Temperature Rise Test
3. Lightning & Switching -Impulse
4. Wet Dielectric Test
5. Determination of errors
6. Radio interference test

5.7.3 Special requirements for type tests

5.7.3.1 Short Time and Peak Current Withstand Test

The peak current must be 2.7 times the r.m.s. rated short circuit current to account for higher
system X/R ratios. The peak current required is higher than the standard 2.5 times.
The test must be carried out to prove thermal withstand at the r.m.s. current specified with a test
duration of 1 second.
For the tests, the secondary windings must be short circuited on the ratio marked on the rating
plate which gives the highest current densities for any part of the secondary winding.

5.7.4 Special Type Tests

The following are special type test requirements.

5.7.4.1 Chopped Lightning impulse Test
A Chopped Impulse Test in accordance with AS 60044.1-2007, Clause 9.1 must be carried out.

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5.7.4.2 Multiple Chopped Impulse Test

A multiple chopped Impulse Test in accordance with AS 60044.1-2007 as per test procedure in
Annex B must be carried out.

5.7.4.3 ‘Safe’ Failure Mode

Type test evidence that demonstrate an inherent ‘safe’ failure mode should be provided.

5.7.4.4 Secondary Open Circuit (Induced High Voltage) Test

This test is to prove the CT is not damaged by accidental open circuit of secondary windings
while the CT is in service.
With any required protective devices fitted, it must be demonstrated to the satisfaction of SP
AusNet that, as the primary current of sinusoidal waveform is increased up to the rated value,
the maximum voltage appearing at the secondary terminals is limited to the withstand value of
the secondary winding insulation.
This test should also prove the durability of any protective device.

5.8 Routine Tests

The manufacturer, prior to delivery, must perform routine Tests to prove compliance with the
Required Performances. The routine tests must be in accordance with AS60044.1–2007 and
SP AusNet agreement.
An SP AusNet representative may be present at all routine tests and the supplier must give
reasonable notice, in writing, before such tests are carried out.
Upon completion of any test, the Contractor must forward to SP AusNet certified test sheets in
duplicate showing the results of such test. The test certificates must be delivered within a period
of two weeks of completion of the test and before the current transformers are packed for
shipment.
Such tests as the Engineer may deem necessary to satisfy himself that the Equipment conforms
to this Contract will be carried out by SP AusNet after delivery.
SP AusNet requires Routine tests in accordance with AS 60044.1-2007 must be performed with
the following additions:

5.8.1 Standard Routine Tests

Standard routine tests as listed in AS 60044.1 -2007 to be carried out are listed below.
1. Verification of terminal markings and name plates
2. Power Frequency Withstand and Partial Discharge Measurement on primary
windings.
3. Power Frequency Withstand Tests on secondary windings
4. Inter-turn Overvoltage Test
5. Determination of errors

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5.8.2 Special requirements for Routine Tests

The average temperature of the current transformer must be recorded for all tests.
5.8.2.1 Partial Discharge Test
A partial discharge test must be performed in conjunction with an applied high voltage test. The
equipment used for the test must permit continuous visual observance of the discharges with
variation of voltage and must have a sensitivity of not less than 5 Pico coulombs. The inception
and extinction voltage of discharges must be recorded.
The nominated maximum values of partial discharges specified in the Schedule of Minimum
Performances must not be exceeded for both ascending and descending test voltages.
5.8.2.2 Inter turn over voltage test
Each type of current transformer assembly must be subjected to open-circuited induced high
voltage tests with protective devices removed, if fitted to prevent flashovers as per item 5.2.12.
With the protective devices removed, each secondary winding must be tested to the withstand
levels specified in Schedule of Minimum Performances.

5.8.3 Special Routine Tests

The following are the additional routine test requirements.

5.8.3.1 Lightening impulse withstand test on primary insulation

This is to be the first routine test carried out. Tests should be performed in Accordance with
AS60044.1 but with three negative and at 100% BIL with zero failures. This test should be
performed before the power frequency tests carried out under standard routine tests.

5.8.3.2 Overvoltage test on protective devices

This test is to prove that any protective devices, required to limit over voltages for accidental
open circuit of secondary windings, are correctly configured.
Protective devices can be bench tested to confirm the correct operation level or mounted in the
CT as per final assembly. If tested mounted on the CT, the CT primary current must be
increased to the point where the protective devices operate and the secondary terminal voltage
measured. The protective device operating voltage shall be confirmed as set below the rated
withstand secondary insulation level. The results shall be confirmed in the routine test report.
5.8.3.3 Capacitance and Dielectric Dissipation Factor
Dielectric Dissipation Factor and capacitance measurements must be carried out on each single-
phase post current transformer as per AS60044.1Section 9.2 and 5.1.2.4.
Measurement of capacitance and dielectric loss angle must be made between the line terminal
and capacitor tapping (if fitted) or dielectric loss angle tapping with all other insulation paths
excluded by guarding.
Between capacitor tapping or dielectric loss angle tapping and tank with all secondary windings
and normally earthed shields connected to tank and with the line terminal guarded.

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5.8.3.4 Oil Quality Analysis

This is the last routine test to be carried out. Oil quality analysis tests must be carried out on
each oil based current transformer supplied prior to delivery.
A chemical analysis must be performed on oil from each oil insulated CT after completion
of the routine electrical tests.
The chemical analysis must measure the ppm of the following:
• Dissolved Gas – to include combustible gases H2, C2H2, C2H4, C2H6, and O2, N2,
CO2, CO and tested to IEC60567;
• Moisture levels, tested to IEC 60814;
• Acidity levels, tested to IP64.
The supplier must provide oil analysis test reports for each CT with the delivered item.

5.8.3.5 Performance Tests: Protection Cores

A secondary exciting current test must be carried out on each secondary winding of each
protective type current transformer completely assembled in its final housing as follows:
The test must be carried out in accordance with Clause 14.4.1 of AS 60044.1-2007, on the ratio
or ratios for which the Rated Knee Point Voltage, Ek, has been specified. The exciting current at
Rated Ek and 110% Rated Ek must be recorded.
On the complete secondary winding, the excitation characteristic must be plotted up to 150%
rated knee point voltage. The measuring points must be 5%, 30%, 60%, 100%, 120% and
150% of Rated Ek.
The windings of all other cores must be short-circuited during the above tests. All readings for
the test must be recorded on the test certificate.

5.8.3.6 Performance Tests: Metering Cores

Tests must be carried out on each specified ratio of each metering current transformer to prove
compliance with Clause 11.4 of AS 60044.1-2007.
The errors for metering current transformers must be recorded at 5%, 20%, 100% and 120% of
rated primary current and at 25% and 100% of rated burden.
For each secondary winding of each metering type current transformer completely assembled in
its housing, the secondary exciting current must be measured (and recorded on the test
certificate) at a voltage at, or about, the knee point on the maximum ratio (i.e. full winding).

5.9 TESTS AFTER DELIVERY

SP AusNet will carry out such tests, as it may deem necessary to satisfy itself that the plant
conforms to the Technical Standard.

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6 SAFETY REQUIREMENTS

This section highlights and repeats the minimum SP AusNet safety requirements associated
over the life cycle of the Current Transformers to meet the operation & maintenance safety
procedural requirements to minimise work place risks and hazards. These are mandatory and
noncompliance will result in non-compliant offer and they must be shown in supplied drawings.

6.1 Insulator Housing

The insulator housing of current transformers shall be high temperature vulcanised (HTV)
silicone rubber composite material. The type of housing shall be nominated by the Tenderer.
The colour of the polymer enclosures must be a light blue-grey or light grey to AS 2700 (B44 or
N22 or equivalent). Brown insulators are not acceptable.
Consideration will be given for epoxy resin type for 24kV current transformers must be at the
sole discretion of the SP AusNet.
6.2 Insulating Liquid
The Tender must state what dielectric liquid is used in the CTs. If oil is used, the brand, grade
(inhibited or non-inhibited) dielectric strength, dielectric dissipation factor, acidity, flashpoint,
viscosity and resistivity must be stated. If any other dielectric is proposed, a full and detailed
description, including composition, flammability and toxicity, must be supplied.
Tenderers must provide a Material Safety Data Sheet and Material Technical Data Sheet for the
dielectric liquid that will be used in the CTs.
Wherever the word “oil” appears in relation to a dielectric in this Technical Standard and the
annexed schedules, it must be deemed to include any other liquid dielectric that may be
supplied.
6.3 Oil sampling and filling
Provision shall be made in oil filled post type current transformers for sampling for condition
monitoring and filling. Clear instructions in the maintenance manual shall be provided for taking
samples for DGA analysis.
6.4 Oil Level and Nitrogen Pressure Indicators
Oil filled current transformers must have an oil level indicator in bellows type construction, or a
nitrogen pressure indicator in nitrogen-cushion type construction. It must be possible to read
indicators while standing on the ground. Any current transformers with nitrogen cushions must
preferably have oil levels above any sealing points.
It must be possible to recharge the nitrogen space without passing nitrogen past paper
insulation.

6.5 Special Environmental: Toxicology Safety

The Tenderer shall provide full details, including composition and toxicological information,
regarding the health and safety aspects of the materials offered in their products that are known
to have risks to health or the environment.
Recommended procedures shall be provided for the safe handling, safe operation and
maintenance of products supplied. The means of disposal of the materials shall be stated.
Material safety data sheets shall be provided, with copies available on site, for materials that are
supplied and subject to safety considerations in handling and use.

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SCHEDULE OF REVISIONS
Issue Date Details of Change Updated by
1 14/12/2006 Original version

2 04/10/2011 Added outdoor 22kV & 245kV special CTs for HWTS N. Boteju
and minor amendments.

3 05/10/2012 Amendments to items and CT specification, added N. Boteju

safety requirements section.
A. Palamarczuk

4 27/03/2013 New item 2: 24kV current transformers for capacitor

banks added.
N. Boteju
Note:
A. Palamarczuk
Guaranteed Performance under item 4.1 for other
current transformers are under review.

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APPENDIX A – DRAWINGS

The following drawings referred to in this Technical Standard will accompany and form part of
this Technical Standard:

Description Drawing Number Rev

Arrangement of cores on CT T14/159/ 363/1
Arrangement of cores on CT T14/159/ 363/ 2

Standard Padlock – Outline Dimensions T14/316/32A

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APPENDIX B – TENDER RESPONSE SCHEDULES

The following schedules are provided for issue as the performance schedules for the Request
for Tender (RFT) for the equipment.

Subsequent to the final negotiation the schedules, complete with the agreed data, will be
included in the Contract as the agreed performance standards.

NOTE: It is important that the data is entered correctly entered as the final agreed information is
copied directly into corresponding fields in the asset management and work planning database
as future reference for this make and type of equipment.

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SCHEDULE 1– Guaranteed Performance Schedule - 24 kV Current Transformers (item 1)

The following table shows the performances the Tenderer guarantees the offered plant will be capable of:

Item
No. Particulars Unit CT Type

ITEM NUMBER 1
CURRENT TRANSFORMERS 1500//1200/600/5
1 With which Standard does current transformer comply?

2 Type of Current Transformer

3 Maximum Continuous Operating Voltage kV

4 Rated Frequency Hz

5 Rated Primary Current (At 50 ºC) A rms.

6 Is design capable of operating up to 50 ºC at reduced

primary current rating?
• Maximum ambient operating temperature;
ºC
• Primary current capability at this temperature. A rms.

7 Short Time Current Rating:

• Three second; A rms.
• Peak current kA Peak

8 Flashover Voltages of External Insulation

8.1 Rated Lightning Impulse Withstand Voltage :
• Phase to Earth kV Peak

8.2 Minimum 50 Hz Dry Flashover Voltage:

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Item
No. Particulars Unit CT Type

ITEM NUMBER 1
CURRENT TRANSFORMERS 1500//1200/600/5
• Phase to Earth kV rms.
• Time of Withstand Seconds

8.3 Minimum 50 Hz Wet Flashover Voltage:

• Phase to Earth kV rms.
• Time of Withstand Seconds

9 Dielectric strength test each current transformer will

withstand for 60 seconds:
• Between primary winding and secondary
kV rms.
winding & Core;
• Between secondary winding & core
kV rms.

10 Maximum internal partial discharge at 120% of

Maximum Continuous Primary Phase to Earth voltage.

11 Are there any of the nominated ratios for which there is Yes/No
not full primary fault current withstand.

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Item
Particulars Unit CT Type
No.
CURRENT TRANSFORMERS 1500/1200/600/5
Protection Current Transformer Cores
12 Rated Transformation Ratios A rms.

12.1 Number of protection cores

13 Performance

13.1 Rated Knee Point Voltage, Ek, on Ratios. V rms. Ratio Rated Ek

1500/5

Do the protection cores comply with the Yes/No

required knee point voltages on all other ratios
available in CT including those between taps

13.2 Maximum Exciting Current, Ie, on Ratios. A rms. Ratio Maximum Ie

1500/5

Do the protection cores comply with the Yes/No

required secondary exciting current on all
other ratios available in CT including those
between taps

13.3 Maximum Resistance, Rct, of Secondary Ohms Ratio Maximum Rct

Windings on Ratios
1500/5

Do the protection cores meet the required Yes/No

resistance of the secondary windings on all
ratios on the CT, including those ratios
between taps, as shown in the minimum
performance requirement sheet ?

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Item
Particulars Unit CT Type
No.
13.4 Continuous Current Rating of secondary Amps Ratio Amps
Windings, on Ratios:
1500/5

Do the secondary windings meet the required Yes/No

current ratings on all ratios on the CTs,
including those ratios between taps, as shown
in the minimum performance requirements
sheet?

14 Do the current transformers contain different Yes/No

gauges of secondary wiring conductor?

15 Do the current transformers contain design air

gaps that modify transient performance and
residual flux?

Measuring Current Transformer Core 1500/1200/600/5

17 Available Current ratios

18 Rated output

19 Accuracy Class

20 Continuous Current Rating of Secondary

Winding (All Ratios):

Protection and Measuring Cores

21 Are the current transformers capable of
withstanding voltage induced by open-
circuiting secondary windings with rated
primary current flowing?

22 Secondary Winding Rated insulation kV rms.

withstand voltage, for 1 minute.

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.

CURRENT TRANSFORMERS 1500/1200/600/5

Metering Current Transformer Core 1500/1200/600/5

23 Secondary Winding Rated Inter-turn insulation kV Peak

voltage, for 1 minute.

24 Secondary Terminals insulation withstand kV Peak.

voltage, for 1 minute.

25 What method is proposed for protection against

damage due to flashover if the secondary
windings are open circuited?

26 Operating voltage of secondary protection

device?

27 Is secondary Protection Device capable of kV Peak

continuous operation? If not, state rated period in
minutes.

28 Maximum permissible mechanical loading on

each Primary Terminal, in the following directions:
• Horizontal, along axis of Terminal;
kN
• Horizontal, perpendicular to axis of kN
Terminal;
Vertical

29 What is the design Wind Loading capability of the ken

CT structures with the CTs mounted?

30 Is apparatus guaranteed to use oil that complies

with Class 1 of AS 1767.1-1999?

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.

For epoxy cast resin type current

transformers
31 Description of dielectric material used (brand ,
grade , composition)

32 Limit of temperature rise and insulation class

33 Product processing method

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 1– Guaranteed Performance Schedule - 24 kV Current Transformers (Item 2)

The following table shows the performances the Tenderer guarantees the offered plant will be capable of:

Item
No.
Particulars Unit CT Type

ITEM NUMBER CT Core 1 CT Core 2

CURRENT TRANSFORMERS (Protection Cores) 1500//1200/600/5 1600/1200/900/5

1 With which Standard does current transformer comply?

2 Type of Current Transformer

3 Maximum Continuous Operating Voltage kV

4 Rated Frequency Hz

5 Rated Primary Current (At 40 ºC) A rms.

6 Is design capable of operating up to 50 ºC at reduced

primary current rating?
• Maximum ambient operating temperature;
ºC
• Primary current capability at this temperature. A rms.

7 Short Time Current Rating:

• Three second; A rms.
• Peak current kA Peak

8 Flashover Voltages of External Insulation

8.1 Rated Lightning Impulse Withstand Voltage :
• Phase to Earth kV Peak

8.2 Minimum 50 Hz Dry Flashover Voltage:

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Outdoor Current Transformers –Equipment Specification

Item
No. Particulars Unit CT Type

ITEM NUMBER CT Core 1 CT Core 2

CURRENT TRANSFORMERS (Protection Cores) 1500//1200/600/5 1600/1200/900/5
• Phase to Earth kV rms.
• Time of Withstand Seconds

8.3 Minimum 50 Hz Wet Flashover Voltage:

• Phase to Earth kV rms.
• Time of Withstand Seconds

9 Dielectric strength test each current transformer will

withstand for 60 seconds:
• Between primary winding and secondary
kV rms.
winding & Core;
• Between secondary winding & core
kV rms.

10 Maximum internal partial discharge at 120% of

Maximum Continuous Primary Phase to Earth voltage.

11 Are there any of the nominated ratios for which there is Yes/No
not full primary fault current withstand.

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.
CURRENT TRANSFORMERS 1500/1200/600/5 1600/1200/900/5
Protection Current Transformer Cores
12 Rated Transformation Ratios A rms.

12.1 Number of protection cores

13 Performance

13.1 Rated Knee Point Voltage, Ek, on Ratios. V rms. Ratio Rated Ek Ratio Rated Ek

1500/5 1600/5

Do the protection cores comply with the required knee Yes/No

point voltages on all other ratios available in CT
including those between taps

13.2 Maximum Exciting Current, Ie, on Ratios. A rms. Ratio Maximum Ie Ratio Maximum Ie
1500/5 1600/5

Do the protection cores comply with the required Yes/No

secondary exciting current on all other ratios available
in CT including those between taps

13.3 Maximum Resistance, Rct, of Secondary Windings on Ohms Ratio Maximum Rct Ratio Maximum Rct
Ratios
1500/5 1600/5

Do the protection cores meet the required resistance Yes/No

of the secondary windings on all ratios on the CT,
including those ratios between taps, as shown in the
minimum performance requirement sheet ?

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.
13.4 Continuous Current Rating of secondary Windings, on Amps Ratio Amps Ratio Amps
Ratios:
1500/5 1600/5

Do the secondary windings meet the required current Yes/No

ratings on all ratios on the CTs, including those ratios
between taps, as shown in the minimum performance
requirements sheet?

14 Do the current transformers contain different gauges of Yes/No

secondary wiring conductor?

15 Do the current transformers contain design air gaps

that modify transient performance and residual flux?

Measuring Current Transformer Core 1200/600/400/5

17 Available Current ratios

18 Rated output

19 Accuracy Class

20 Continuous Current Rating of Secondary Winding (All

Ratios):

Protection and Measuring Cores

21 Are the current transformers capable of withstanding
voltage induced by open-circuiting secondary windings
with rated primary current flowing?

22 Secondary Winding Rated insulation withstand kV rms.

voltage, for 1 minute.

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.

CURRENT TRANSFORMERS
Protection and Measuring Cores (Cont’d)

23 Secondary Winding Rated Inter-turn insulation kV Peak

voltage, for 1 minute.

24 Secondary Terminals insulation withstand kV Peak.

voltage, for 1 minute.

25 What method is proposed for protection against

damage due to flashover if the secondary
windings are open circuited?

26 Operating voltage of secondary protection

device?

27 Is secondary Protection Device capable of kV Peak

continuous operation? If not, state rated period in
minutes.

28 Maximum permissible mechanical loading on

each Primary Terminal, in the following directions:
• Horizontal, along axis of Terminal;
kN
• Horizontal, perpendicular to axis of kN
Terminal;
Vertical

29 What is the design Wind Loading capability of the kN

CT structures with the CTs mounted?

30 Is apparatus guaranteed to use oil that complies

with Class 1 of AS 1767.1-1999?

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.

For epoxy cast resin type current

transformers
31 Description of dielectric material used (brand ,
grade , composition)

32 Limit of temperature rise and insulation class

33 Product processing method

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 1 – Guaranteed Performance Schedule - 72.5 kV Current Transformers

The following table shows the performances the Tenderer guarantees the offered plant will be capable of:
Item
No. Particulars Unit CT Type CT Type

ITEM NUMBER 3 4
CURRENT TRANSFORMERS 2100/1600/1200/900/5 3000/2100/1600/1200/5
1 With which Standard does current transformer comply?

2 Type of Current Transformer

3 Maximum Continuous Operating Voltage kV

4 Rated Frequency Hz

5 Rated Primary Current (At 50 ºC) A rms.

6 • Is design capable of operating up to 50 ºC at Yes/No

rated primary current?
• If not what is the primary current rating at this A rms.
temperature Maximum ambient operating
temperature?
• What is the maximum ambient operating
temperature at which rated primary current is ºC
available?

7 Short Time Current Rating:

• Three second; A rms.
• Peak current kA Peak

8 Flashover Voltages of External Insulation

8.1 Rated Lightning Impulse Withstand Voltage :
• Phase to Earth kV Peak

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Outdoor Current Transformers –Equipment Specification

Item
No. Particulars Unit CT Type CT Type

ITEM NUMBER 3 4
CURRENT TRANSFORMERS 2100/1600/1200/900/5 3000/2100/1600/1200/5
8.2 Minimum 50 Hz Dry Flashover Voltage:
• Phase to Earth kV rms.
• Time of Withstand Seconds

8.3 Minimum 50 Hz Wet Flashover Voltage:

• Phase to Earth kV rms.
• Time of Withstand Seconds

9 Dielectric strength test each current transformer will

withstand for 60 seconds:
• Between primary winding and secondary
kV rms.
winding & Core;
• Between secondary winding & core
kV rms.

10 Maximum internal partial discharge at 120% of

Maximum Continuous Primary Phase to Earth voltage.

11 Are there any of the nominated ratios for which there is Yes/No
not full primary fault current withstand.

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type CT Type
No.
CURRENT TRANSFORMERS 2100/1600/1200/900/5 3000/2100/1600/1200/5
Protection Current Transformer Cores
12 Rated Transformation Ratios A rms.

13 • Performance

13.1 Rated Knee Point Voltage, Ek, on Ratios. V rms. Ratio Rated Ek Ratio Rated Ek

2100/5 3000/
5

Do the protection cores comply with the Yes/No

required knee point voltages on all other ratios
available in CT including those between taps

13.2 Maximum Exciting Current, Ie, on Ratios. A rms. Ratio Maximum Ie Ratio Maximum Ie

2100/5 3000/
5

Do the protection cores comply with the Yes/No

required secondary exciting current on all other
ratios available in CT including those between
taps

13.3 Maximum Resistance, Rct, of Secondary Ohms Ratio Maximum Rct Ratio Maximum Rct
Windings on Ratios
2100/5 3000/5

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type CT Type
No.
Do the protection cores meet the required Yes/No
resistance of the secondary windings on all
ratios on the CT, including those ratios between
taps, as shown in the minimum performance
requirement sheet ?

13.4 Continuous Current Rating of secondary Amps Ratio Amps Ratio Amps
Windings, on Ratios:
2100/5 3000/
5

Do the secondary windings meet the required Yes/No

current ratings on all ratios on the CTs,
including those ratios between taps, as shown
in the minimum performance requirements
sheet?

14 Do the current transformers contain different Yes/No

gauges of secondary wiring conductor?

15 Are the current transformers of low leakage

reactance design on all nominated ratios?

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type CT Type
No.

CURRENT TRANSFORMERS 2100/1600/1200/900/5 3000/1600/1200/5

16 Do the current transformers contain design air gaps

that modify transient performance and residual flux?

Protection – Measuring Current Transformer

Cores

17a Does the combined Protection –Measuring core Yes/No

meet the required performance classifications and
requirements as set out in the Minimum Performance
Requirements for protection and measuring functions

17b If not, please indicate the required clarification and

/or requirements that are not met, and what
alternative clarifications and requirements are
offered.

Measuring Current Transformer Core

18 Continuous Current Rating of Secondary Winding
(All Ratios):

Protection and Measuring Cores

19 Are the current transformers capable of withstanding
voltage induced by open-circuiting secondary
windings with rated primary current flowing?

20 Secondary Winding Rated insulation withstand kV rms.

voltage, for 1 minute.

21 Secondary Winding Rated Inter-turn insulation kV

voltage, for 1 minute. Peak

22 Secondary Terminals insulation withstand voltage, kV

for 1 minute. Peak.

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Item
Particulars Unit CT Type CT Type
No.
23 What method is proposed for protection against
damage due to flashover if the secondary windings
are open circuited?

24 Operating voltage of secondary protection device?

25 Is secondary Protection Device capable of kV

continuous operation? If not, state rated period in Peak
minutes.

26 Maximum permissible mechanical loading on each

Primary Terminal, in the following directions:
• Horizontal, along axis of Terminal;
kN
• Horizontal, perpendicular to axis of Terminal; kN
Vertical

27 What is the design Wind Loading capability of the CT kN

structures with the CTs mounted?

28 Is apparatus guaranteed to use oil that complies with

Class 1 of AS 1767.1-1999?

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 1 – Guaranteed Performance Schedule - 245 kV Current Transformers

The following table shows the performances the Tenderer guarantees the offered plant will be capable of:
Item No. Particulars Unit CT Type CT Type CT Type
CT Type
ITEM NUMBER 8 7 6 5

CURRENT TRANSFORMERS 3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5

& 2000/1.25 (40 kA) (50 kA) (50 kA)
(50 kA)

1 With which Standard does current transformer

comply?

2 Type of Current Transformer

3 Maximum Continuous Operating Voltage kV

4 Rated Frequency Hz

5 Rated Primary Current (at 40 ºC) A rms

6 • Is design capable of operating up

to 50 ºC at rated primary current?
Yes/No
• If not what is the primary current
rating at this temperature
Maximum ambient operating A rms.
temperature?
• What is the maximum ambient
operating temperature at which
rated primary current is available? ºC
7 Short Time Current Rating:
• One second A rms.
• Peak current kA Peak
8 Flashover Voltages of External
Insulation

8.1 Rated Lightning Impulse Withstand Voltage, Phase

to Earth
kV Peak

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Item No. Particulars Unit CT Type CT Type CT Type

ITEM NUMBER 8 7 6 5

CURRENT TRANSFORMERS 3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5

& 2000/1.25 (40 kA) (50 kA) (50 kA)
(50 kA)

8.2 Minimum 50 Hz Dry Flashover Voltage:

• Phase to Earth
• Time of Withstand kV rms.
Seconds
8.3 • Minimum 50 Hz Wet Flashover Voltage: kV rms.
Phase to Earth
• Time of Withstand
Seconds

9 Dielectric strength test each current transformer will

withstand for 60 sec.
• Between primary winding and secondary
winding & core; kV rms.
• Between secondary winding & core.

kV rms.
10 Maximum internal partial discharge at 120% of pC
Maximum Continuous Primary Phase to Earth voltage
rated phase to earth voltage.

PROTECTION CURRENT TRANSFORMER CORES

11 Rated Transformation Ratios A rms

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Item No. Particulars Unit CT Type CT Type CT Type CT Type

CURRENT TRANSFORMERS 3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5

& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)

12 Performance

12.1 Rated Knee Point Voltage, Ek, on Ratios: V rms Ratio Minimum Ek Ratio Minimum Ratio Minimum Ek Ratio Minimum Ek
Ek

3000/5 3000/5 4000/5 3000/5

Do the protection cores comply with the Yes/

required knee point voltages on all other No
ratios available in CT including those
between taps

Rated Knee Point Voltage, Ek, on Ratios: V rms 2000/1.25 (core 2) 600/5

12.2 Maximum Exciting Current, Ie, on Ratios: A rms Ratio Maximum Ie Ratio Maximum Ratio Maximum Ie Ratio Maximum Ie
Ie

3000/5 3000/5 4000/5 3000/5

Do the protection cores comply with the Yes/

required secondary exciting current on all
No
other ratios available in CT including those
between taps?

Maximum Exciting Current, Ie, on Ratios: A rms 2000/1.25 (core 2)

12.3 Maximum Resistance, Rct, of Secondary ohms Ratio Maximum Ratio Maximum Ratio Maximum Ratio
Windings at 75 ºC, on Ratios: Rct Rct Rct

3000/5 3000/5 4000/5 3000/5

Do the protection cores meet the required Yes/

resistance of the secondary windings on all
ratios on the CT, including those ratios
No
between taps, as shown in the minimum
performance requirement sheet?

Maximum Resistance, Rct, of Secondary ohms 2000/1.25 (core 2)

Windings at 75 ºC, on Ratios:

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Outdoor Current Transformers –Equipment Specification

ITEM NUMBER 8 7 6 5

Item No. Particulars Unit CT Type CT Type CT Type

CT Type

CURRENT TRANSFORMERS Unit 3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5

& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)

12.4 Continuous Current Rating of Secondary amps Ratio Amps rms. Ratio Amps rms. Ratio Amps rms. Ratio Amps rms.
Windings, on Ratios:
3000/5 3000/5 4000/5 3000/5

Do the secondary windings meet the Yes/

required current ratings on all ratios on the
No
CTs, including those ratios between taps, as
shown in the minimum performance
requirements sheet?

Continuous Current Rating of Secondary amps 2000/1.25 (core 2)

Windings, on Ratios:

13 Do the current transformers contain different

gauges of secondary wiring conductor?

14 Are the current transformers of low leakage

reactance design on all nominated ratios?

15 Do the Current Transformer Cores contain Yes/N

air gaps to modify transient performance and o
residual flux?

Protection –Measuring current

transformer cores

15a Does the combined Protection –Measuring Yes/N

core meet the required performance o
classifications and requirements as set out
in the Minimum Performance Requirements
for protection and measuring functions

15b If not, please indicate the required

clarification and /or requirements that are not
met, and what alternative clarifications and
requirements are offered.

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Outdoor Current Transformers –Equipment Specification

ITEM NUMBER 8 7 6 5

Item No. Particulars Unit CT Type CT Type CT Type

CURRENT TRANSFORMERS 3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5

& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)

Measuring Current Transformer Core (1)

16 Rated Transformation Ratios

17 Rated output ,each ratio VA

18 Accuracy Class ,each ratio

19 Continuous Current Rating of Secondary A rms.

Winding (All Ratios):

Measuring Current Transformer Core (11)

20 Rated Transformation Ratios

21 Rated output ,each ratio VA

22 Accuracy Class ,each ratio

23 Continuous Current Rating of Secondary A rms.

Winding (All Ratios):

Protection and Measuring Cores

24 Are the current transformers capable of

withstanding voltage induced by open-
circuiting secondary windings with rated
primary current flowing?

26 Will routine secondary open-circuit induced

high voltage tests be carried out on
unmounted CT cores prior to assembly in
accordance with the Clause headed Current
Transformer Routine Tests?

27 Secondary Winding Rated insulation kV

withstand voltage, for 1 minute. rms.

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Outdoor Current Transformers –Equipment Specification

Item No. Particulars Unit CT Type CT Type CT Type

3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5
CURRENT TRANSFORMERS
& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)

Protection and Measuring Cores

28 Secondary Winding Rated Inter-turn kV

insulation voltage, for 1 minute. Peak

29 Secondary terminals insulation withstand kV

voltage, for 1 minute. Peak

30 What method is proposed for protection

against damage due to flashover if the
secondary windings are open circuited?

31 Operating voltage of secondary protection kV

device Peak

32 Is secondary Protection Device capable of

continuous operation? If not, state rated
period in minutes.

33 Is the CT guaranteed to withstand the Short Yes/N

Time Current Withstand Test described in o
F4.4 on the ratio which gives the highest
current densities for any part of the
secondary winding?

34 Is voltage tap fitted?

35 Material used for voltage tap bushing

36 Can bushing be fully enclosed?

37 Maximum output when Electromagnetic VA

device fitted.

38 Open circuit voltage of voltage tap kV

39 Maximum permissible mechanical loading on

each Primary Terminal, in the following
directions: kN
• Horizontal, along axis of Terminal;
• Horizontal, perpendicular to axis of kN
Terminal:
• Vertical. kN

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Item No. Particulars Unit CT Type CT Type CT Type

3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5
CURRENT TRANSFORMERS
& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)

40 What is the design Wind Loading capability kN

of the CT mounting structures with the CTs

41 Is apparatus guaranteed to use oil that

complies with Class 1 of AS 1767.1 – 1999?

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 1– Guaranteed Performance Schedule - 362 kV Current Transformers

The following table shows the performances the Tenderer guarantees the offered plant will be capable of:

Item
Particulars Unit CT Type
No.

ITEM NUMBER 9
CURRENT TRANSFORMERS 3000/2000/1600/1200/1 (50 kA)
1 With which Standard does current transformer
comply?

2 Type of Current Transformer Post type

3 Maximum Continuous Operating Voltage kV

4 Rated Frequency Hz

5 Rated Primary Current (At 40 ºC) A rms.

6 Is design capable of operating up to an ambient

temperature of 50 ºC at reduced primary current
rating?
A rms.
• Primary current capability at this
temperature.

7 Short Time Current Rating

• One Second A r.m.s.
• Peak Current kA Peak

8 Flashover Voltages of External Insulation

8.1 Lightning Impulse Withstand Voltage
• Phase to Earth kV Peak

8.2 Switching Impulse Withstand level

• Phase to Earth kV Peak

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.
CURRENT TRANSFORMERS 3000/2000/1600/1200/1 (50 kA)
8.3 Minimum 50 Hz Dry flashover voltage
• Phase to Earth kV rms
• Time of Withstand Seconds.

8.4 Minimum 50 Hz Wet flashover voltage

• Phase to Earth kV rms
• Time of Withstand Seconds.

9 Dielectric strength test each current transformer will

withstand for 60 secs.
• Between Primary Winding and Secondary
Winding &Core. kV rms.
• Between Secondary Winding and Core. kV rms.
10 Maximum internal partial discharge at 120% of pC
Maximum Continuous Primary Phase to Earth
voltage.
Protection Current Transformers

11 Rated Transformation Ratios A rms.

Performance

12.1 Rated Knee point Voltage Ek on ratios V rms Ratio Maximum Ie

3000/1
Do the protection cores comply with the required Yes/No
knee point voltages on all other ratios available in CT
including those between taps

12.2 Maximum Exciting Current, Ie, on Tap Ratios A rms. Ratio Maximum Ie
3000/1

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.

Do the protection cores comply with the required Yes/No

secondary exciting current on all other ratios
available in CT including those between taps?

12.3 Maximum Resistance, Rct, of secondary Windings at Ohms Ratio Maximum Rct
75 ºC, on Tap Ratios
3000/1
Do the protection cores meet the required resistance Yes/No
of the secondary windings on all ratios on the CT,
including those ratios between taps, as shown in the
minimum performance requirement sheet ?

12.4 Continuous Current Rating of Secondary Windings, A rms. Ratio Amps

on Tap Ratios
3000/1
Do the secondary windings meet the required Yes/No
current ratings on all ratios on the CTs, including
those ratios between taps, as shown in the minimum
performance requirements sheet?

13 Maximum Exciting Current, Ie, at % Rated Knee A rms % Rated Ek. Exciting
Point Voltage Ek 4% Current, Ie

14 Do the current transformers contain different wiring

gauges for the secondary windings?

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.
CURRENT TRANSFORMERS 3000/2000/1600/1200/1 (50kA)
15 Are the Current Transformers of Low Leakage
Reactance design on all nominated ratios?

16 Do the Current Transformers contain air gaps that

modify transient performance and residual Flux?

Measuring Current Transformer Core

17 Rated Transformation Ratio

18 Rated Output VA

19 Accuracy Class

20 Continuous Current Rating of Secondary Windings

A rms.
(All Ratios)

Protection and Measuring Cores

21 Are the current transformers capable of
withstanding voltage induced by open-circuiting
secondary winding for one minute with rated
primary current flowing?

22 Will routine secondary o/c induced high voltage

tests be carried out on unmounted CT cores prior to
assembly in accordance with the Clause headed
Current Transformer Routine Tests?

23 Secondary Winding Rated Insulation Withstand kV rms.

Voltage, for 1 minute?

24 Secondary Winding Rated Inter-turn Insulation kV

Voltage, for 1 minute? Peak.

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.

CURRENT TRANSFORMERS 3000/20/00/1600/1200/1 (50 kA)

Protection and Measuring Cores
25 Secondary Terminals Insulation Withstand kV Peak
Voltage

26 What method is proposed for protection

against damage due to flashover if the
secondary windings become open circuited?

27 Operating voltage of Secondary Protective kV Peak

Device?

28 Is Secondary Protective Device capable of

continuous operation?

29 Is the CT guaranteed to withstand the Short

Time Current Withstand Test described in
F4.4 on the ratio which gives the highest
current densities for any part of the secondary
winding?

Voltage Tap (If Applicable)

30 Is voltage tap fitted?

31 Material used for voltage tap bushing

32 Can bushing be fully enclosed?

33 Maximum output when Electro Magnetic VA

device fitted.

34 Open circuit voltage of Voltage Tap kV

35 Maximum permissible mechanical loading on

each Primary terminal, in the following

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.
directions:
• Horizontal, along axis of Terminal;
kN
• Horizontal, perpendicular to axis of
Terminal; kN
• Vertical. kN

36 What is the design Wind Loading capability of

the CT mounting structures with the CTs
mounted?
kN

37 Is the apparatus guaranteed to use oil that

complies with Class1 of AS 1767.1-1999?

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 1 – Guaranteed Performance Schedule - 550 kV Current Transformers (CTS with 1 Amp Secondary Rating Cores)
The following table shows the performances the Tenderer guarantees the offered plant will be capable of:

Item
Particulars Unit CT Type
No.
ITEM NUMBER 10
CURRENT TRANSFORMERS 4000/3000/2500/1 (63 kA)
1 With which Standard does current
transformer comply?

2 Type of Current Transformer Post type

3 Maximum Continuous Operating

Voltage
kV

4 Rated Frequency Hz

5 Rated Primary Current (at 40 ºC) A rms.

6 Is design capable of operating up

to 50 ºC at reduced primary current
rating?
• Primary current capability Amps
at this temperature. rms.

7 Short time Current Rating A rms.

• One second
• Peak current kA Peak

Flashover Voltages of
External Insulation
8.1 Rated Lightning Impulse Withstand
Voltage Phase to Earth
kV Peak

8.2 Switching Impulse Withstand level

Phase to Earth
kV Peak

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Outdoor Current Transformers –Equipment Specification

Item No. Particulars Unit CT Type

CURRENT TRANSFORMERS 4000/3000/2500/1 (63 kA)
8.3 Minimum 50 Hz Dry Withstand voltage
• Phase to Earth kV rms
• Time of Withstand Seconds.
8.4 Minimum 50 Hz Wet Withstand voltage
• Phase to Earth kV rms
• Time of Withstand Seconds.
9 Dielectric strength test each current transformer
will withstand for 60 secs.
• Between primary winding and kV rms.
Secondary Winding & Core.
• Between Secondary Winding and Core. kV rms.
10 Maximum internal partial discharge at 120% of pC
Maximum Continuous Primary Phase to Earth
voltage.

Protection Current Transformer Cores

11 Rated Transformation Ratios A rms.

12 • Performance
12.1 Rated Knee Point Voltage, Ek, on Ratios. V rms. Ratio Ek

4000/1

Do the protection cores comply with the Yes/No

required knee point voltages on all other ratios
available in CT including those between taps

12.2 Maximum Exciting Current, Ie, on Tap Ratios. A rms. Ratio Ie

4000/1

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Outdoor Current Transformers –Equipment Specification

Item No. Particulars Unit CT Type

Do the protection cores comply with the Yes/No
required secondary exciting current on all other
ratios available in CT including those between
taps ?

12.3 Maximum Resistance, Rct, of Secondary Ohms Ratio Rct

Windings on ratios
4000/1
Do the protection cores meet the required Yes/No
resistance of the secondary windings on all
ratios on the CT, including those ratios between
taps, as shown in the minimum performance
requirement sheet ?

12.4 Continuous Current Ratings of Secondary A rms. Ratio amps

Windings:
4000/1

Do the secondary windings meet the required Yes/No

current ratings on all ratios on the CTs,
including those ratios between taps, as shown
in the minimum performance requirements
sheet?

13 Maximum Exciting Current at % Rated Knee % Rated Ek Exciting

Point Voltage, Ek Current Ie
4%

14 Do the Current Transformers contain different

wiring gauges for the secondary windings?

15 Are the Current Transformers of low leakage

reactance design on all nominated ratios?

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Outdoor Current Transformers –Equipment Specification

Item No. Particulars Unit CT Type

16 Do the Current Transformer Cores contain air
gaps that modify transient performance and
residual flux?

Measuring Current Transformer Cores

17 Rated Transformation Ratios

18 Rated output ,each ratio VA

19 Accuracy Class, each ratio

20 Continuous Current Rating of Secondary A rms.

Winding (All Ratios):

Protection and Metering Cores

21 Are the current transformers capable of
withstanding voltage induced by open-circuiting
secondary winding for one minute with rated
primary current flowing?

22 Will routine secondary open-circuit induced high

voltage tests be carried out on unmounted CT
cores prior to assembly in accordance with the
Clause headed Current Transformer Routine
Tests?

23 Secondary Winding Rated Insulation Withstand kV rms.

Voltage, for 1 minute

24 Secondary Winding Rated Inter-turn Insulation kV Peak.

Withstand Voltage, for 1 minute

25 Secondary Terminals Insulation Withstand kV Peak

Voltage, for 1 minute.

26 What method is proposed for protection against

damage due to flashover if the secondary
windings become open circuited?

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Outdoor Current Transformers –Equipment Specification

Item No. Particulars Unit CT Type

27 Operating voltage of Secondary Protective
Device

28 Is Secondary Protective Device capable of

continuous operation?

29 Is the CT guaranteed to withstand the Short

Time Current Withstand Test described in F4.4
on the ratio which gives the highest current
densities for any part of the secondary winding?

Voltage Tap (If Applicable)

30 Is voltage tap fitted?

31 Material used for voltage tap bushing

32 Can bushing be fully enclosed?

33 Maximum output when Electro Magnetic device VA

fitted.
34 Open circuit voltage of voltage tap kV
35 Maximum permissible mechanical loading on
each Primary Terminal, in the following
directions:
• Horizontal, along axis of Terminal kN
• Horizontal, perpendicular to axis of kN
Terminal kN
• Vertical
36 What is the design Wind Loading capability of
the CT mounting structures with the CTs
mounted? kN
37 Is apparatus guaranteed to use oil that complies
with Class 1 of AS 1767.1 - 1999?

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 2 – Details of Plant Being Offered – 24 kV Current Transformers (Item 1)

Item
Particulars Unit CT Type
No.

CURRENT TRANSFORMERS 1500/1200/600/5

1 Name of Maker

2 Country of Manufacture

3 Type Designation or Number of CT

4 Type (Dead Tank, Live Tank, Post Type, Bushing Type,

and Oil or epoxy resin)

Dimensions, Weight
5 Overall dimensions of complete unit:
• Width: mm
• Depth; mm
• Height mm
• Total weight (incl. Oil/SF6) kg

6.1 Quantity of Oil required for each Current Transformer Litres

assembly

7 Method of Shipping and Transport (full details to be

included with Tender)

8 Dielectric Dissipation Factor of Oil at 20 ºC and 90 ºC Radian

(maximum value)

9 Resistivity of Oil at 20 ºC and 90 ºC (min.value) Ohm-cm

10 Dielectric Strength of Oil kV

11 Type of Material used for secondary bushings (conductor

stud and the means adopted to prevent oil leakage)

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Outdoor Current Transformers –Equipment Specification

Item
Particulars Unit CT Type
No.

12 Conductor Material used in secondary windings

13 What type of Insulation is used on the secondary winding

wire?

14 Is there an earth shield between the high voltage

conductor and the secondary windings?

15 Effective length of primary bushing between metallic mm

attachment devices

16 Effective creepage distance along bushing mm

17 Is external Spark Gap required to coordinate Insulation
(Post type CT)s?

18 If answer to 17 is Yes, what is recommended gap setting? mm

19 For Post Type CT, what is capacitance and the Dielectric
Dissipation Factor for:
Primary to Capacitance Tap?
Secondaries to Capacitance Tap?
Primary to Remainder?
20 Type of Primary bushing (HTV silicone rubber insulation, HTV silicone
please provide details), and estimated service life? rubber / Epoxy
Years

21 Type of material used in bellows to allow oil, if applicable?

22 Name of testing Authority, place at which the following

Tests will be carried out:
Type Tests; and Routine Tests.
23 Method for indicating level of nitrogen pressurisation (Oil Provide
filled CTs)? details

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 2 – Details of Plant Being Offered – 24 kV Current Transformers (Item 2)

Item CT Type
Particulars Unit CT Type
No.

CURRENT TRANSFORMERS 1500/1200/600/5 1600/1200/900/5

1 Name of Maker

2 Country of Manufacture

3 Type Designation or Number of CT

4 Type (Dead Tank, Live Tank, Post Type, Bushing Type,

and Oil or epoxy resin)

Dimensions, Weight
5 Overall dimensions of complete unit:
• Width: mm
• Depth; mm
• Height mm
• Total weight (incl. Oil/SF6) kg

6.1 Quantity of Oil required for each Current Transformer Litres

assembly

7 Method of Shipping and Transport (full details to be

included with Tender)

8 Dielectric Dissipation Factor of Oil at 20 ºC and 90 ºC Radian

(maximum value)

9 Resistivity of Oil at 20 ºC and 90 ºC (min.value) Ohm-cm

10 Dielectric Strength of Oil kV

11 Type of Material used for secondary bushings (conductor

stud and the means adopted to prevent oil leakage)

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Outdoor Current Transformers –Equipment Specification

Item CT Type
Particulars Unit CT Type
No.

12 Conductor Material used in secondary windings

13 What type of Insulation is used on the secondary winding

wire?

14 Is there an earth shield between the high voltage

conductor and the secondary windings?

15 Effective length of primary bushing between metallic mm

attachment devices

16 Effective creepage distance along bushing mm

17 Is external Spark Gap required to coordinate Insulation
(Post type CT)s?

18 If answer to 17 is Yes, what is recommended gap setting? mm

19 For Post Type CT, what is capacitance and the Dielectric
Dissipation Factor for:
Primary to Capacitance Tap?
Secondaries to Capacitance Tap?
Primary to Remainder?
20 Type of Primary bushing (HTV silicone rubber insulation, HTV silicone
please provide details), and estimated service life? rubber / Epoxy
Years

21 Type of material used in bellows to allow oil, if applicable?

22 Name of testing Authority, place at which the following

Tests will be carried out:
Type Tests; and Routine Tests.
23 Method for indicating level of nitrogen pressurisation (Oil Provide
filled CTs)? details

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 2 – Details of Plant Being Offered – 72.5 kV Current Transformers

Item
Particulars Unit CT Type CT Type
No.

CURRENT TRANSFORMERS 2100/1600/1200/900/5 3000/2100/1600/1200/5

1 Name of Maker

2 Country of Manufacture

3 Type Designation or Number of CT

4 Type (Dead Tank, Live Tank, Post Type, Bushing

Type, and Oil or SF6)

Dimensions, Weight
5 Overall dimensions of complete unit:
• Width: mm
• Depth; mm
• Height mm

• Total weight (incl. Oil/SF6) kg

6.1 Quantity of Oil required for each Current Litres

Transformer assembly

6.2 Quantity of SF6 required for each CT assembly (at kg

normal operating pressure)

7 Method of Shipping and Transport (full details to be

included with Tender)

8 Dielectric Dissipation Factor of Oil at 20 ºC and 90 Radian

ºC (maximum value)

9 Resistivity of Oil at 20 ºC and 90 ºC (min.value) Ohm-cm

10 Dielectric Strength of Oil kV

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Item
Particulars Unit CT Type CT Type
No.
11 Type of Material used for secondary bushings
(conductor stud and the means adopted to prevent
oil or SF6 leakage)

12 Conductor Material used in secondary windings

13 What type of Insulation is used on the secondary

winding wire?

14 Is there an earth shield between the high voltage

conductor and the secondary windings?

15 Effective length of primary bushing between mm

metallic attachment devices

16 Effective creepage distance along bushing mm

17 Is external Spark Gap required to coordinate

Insulation (Post type CT?

18 If answer to 17 is Yes, what is recommended gap mm

setting?

19 For Post Type CT, what is capacitance and the

Dielectric Dissipation Factor for:
Primary to Capacitance Tap?
Secondaries to Capacitance Tap?
Primary to Remainder?
20 Type of Primary bushing (If Polymer, please Years
provide details), and estimated service life?
(Porcelain or Composite)

21 Type of material used in bellows to allow oil, if

applicable?

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Item
Particulars Unit CT Type CT Type
No.
22 Name of testing Authority, place at which the
following Tests will be carried out:
Type Tests; and Routine Tests.
23 Method for indicating level of nitrogen Provide
pressurisation (Oil filled CTs)? details.

24 Type of Gas Density Monitor or Monitors provided Provide

(SF6 filled details.

25 Guaranteed SF6 leakage rate (if applicable) %

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SCHEDULE 2 – Details of Plant Being Offered - 245 kV Current Transformers

Item
Particulars Unit CT Type CT Type CT Type CT Type
No.

ITEM NUMBER 8 7 6 5

3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5

CURRENT TRANSFORMERS
& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)

1 Name of Maker

2 Country of Manufacture

3 Type Designation or Number of

CT

4 Type (Dead Tank, Live Tank,

Post Type, Bushing Type, and
Oil or SF6 filled)

Dimensions, Weight, Quantity

5 Overall dimensions of complete

unit;
mm
• Width;
mm
• Depth;
mm
• Height; kg
• Total weight (incl.
Oil/SF6)

6.1 Quantity of Oil required for each Litres

Current Transformer assembly

6.2 Quantity of SF6 required for kg

each CT assembly (at normal
operating pressure)

7 Method of Shipping and

Transport (Full details to be
included with Tender)

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Item
Particulars Unit CT Type CT Type CT Type CT Type
No.

8 Dielectric Dissipation Factor of Radian

Oil at 20 ºC and 90 ºC
(maximum value)

9 Resistivity of Oil at 20 ºC and 90 Ohm-cm

ºC (minimum value)

10 Dielectric Strength of Oil kV

11 Type of Material used for

Secondary Terminals/Bushings
(conductor stud and the means
adopted to prevent oil or SF6
leakage)

12 Conductor Material used in

secondary windings.

14 Is there an earth shield between

the high voltage conductor and
the secondary windings?

15 Effective length of primary mm

bushing between metallic
attachment devices

16 Effective creepage distance mm

along bushing.

17 Is external Spark Gap required

to coordinate Insulation (Post
type CT)

18 If answer to 17 is Yes, what is mm

recommended gap setting?

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Item
Particulars Unit CT Type CT Type CT Type CT Type
No.
3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5
CURRENT TRANSFORMERS
& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)

19 For Post type CT, what is

Capacitance and the Dielectric
Dissipation Factor for:
• Primary to Capacitance
Tap;
• Secondaries to
Capacitance Tap:
• Primary to remainder.

20 Type of Insulator Shell (If Years

polymer, please provide details),
and estimated service life.

21 Type of Material used in Bellows

to allow oil expansion (If
applicable)

22 Name of Testing Authority, place

at which the following Tests will
be carried out:
• Type Tests;
• Routine Tests
23 Voltage Tap (If Applicable)

23.1 Voltage of Intermediate Voltage

Tap

23.2 Output Burden after

Electromagnetic Unit

23.3 Required condition of

Intermediate Voltage Tap when
not in use.

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Item
Particulars Unit CT Type CT Type CT Type CT Type
No.
3000/2100/1500/5 4000/3000/2100/1500/5 3000/2100/1500/5 3000/2100/1500/5
CURRENT TRANSFORMERS
& 2000/1.25 (50 kA) (40 kA) (50 kA) (50 kA)
24 Oil or SF6 Level Indication

24.1 Method of Indicating level of

nitrogen pressurisation (oil filled
CTs)

24.2 Type of Gas Density Monitor or

monitors provided (SF6 filled
CTs)

25 Guaranteed SF6 leakage rate (if %

applicable)

26 CT Marshalling Box

26.1 Degree of weather protection

26.2 Maker

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SCHEDULE 2 – Details of Plant Being Offered - 362 kV Current Transformers

Item
Particulars Unit CT Type CT Type
No.

CURRENT TRANSFORMERS 3000/2000/1600/1200/1 (40 kA) 3000/2000/1600/1200/1 (50 kA)

1 Name of Maker

2 Country of Manufacture

3 Type Designation or Number of CT

4 Type (Dead Tank, Live Tank, Post Type, Bushing

Type, and Oil or SF6 filled)

Dimensions, Weight, Quantity

5 Overall dimensions of complete unit:
• Width mm
• Depth mm
• Height mm
• Total weight (incl. oil/SF6) kg

6.1 Quantity of Oil required for each Current Transformer Litres

assembly

6.2 Quantity of SF6 required for each CT assembly (at kg

normal operating pressure)

7 Method of Shipping and Transport (full details to be

included with Tender)

8 Dielectric Dissipation Factor of Oil at 20 ºC and 90ºC Radian

(maximum value)

9 Resistivity of Oil at 20 ºC and 90 ºC (minimum value) Ohm-cm

10 Dielectric Strength of oil kV

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Item
Particulars Unit CT Type CT Type
No.
11 Type of Material used for secondary terminals/
bushings (conductor stud and the means adopted to
prevent oil or SF6 leakage)

12 Conductor Material used in secondary windings

13 What type of Insulation is used on the secondary

winding wire?

14 Is there an earth shield between the high voltage

conductor and the secondary windings?

15 Effective length of primary bushing between metallic mm

attachment devices

16 Effective creepage distance along bushing. mm

17 Is external Spark Gap required to coordinate Yes/No

Insulation (Post type CT)?

18 If answer to 17 is Yes, what is recommended gap mm

setting?

19 For Post type CT, what is Capacitance and the

Dielectric Dissipation Factor for:
• Primary to Capacitance Tap;
• Secondary to Capacitance Tap;
Primary to Remainder.

20 Type of Insulator Shell (If polymer, please provide

details), and estimated service life.

21 Type of Material in Oil Expansion Bellows (If

applicable)

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Item
Particulars Unit CT Type CT Type
No.

CURRENT TRANSFORMERS 3000/2000/1600/1200/1 (40 kA) 3000/2000/1600/1200/1 (50 kA)

22 Name of Testing Authority, place at which
following Tests will be carried out.
• Type Tests
• Routine Tests

VOLTAGE TAP (IF APPLICABLE)

23 Voltage of Intermediate Voltage Tap kV rms.

24 Output Burden after Electromagnetic Unit

25 Required condition of Intermediate Voltage Earthed/Un-

Tap when not in use. earthed

CT Marshalling Box
26 Degree of weather protection

27 Maker

Oil or SF6 Level Indication

28 Method of indicating level of nitrogen Provide

pressurisation (oil filled CTs) details

29 Type of Gas Density Monitor or monitors Provide

provided (SF6 filled CTs) details
30 Guaranteed SF6 leakage rate (if applicable) %

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Outdoor Current Transformers –Equipment Specification

SCHEDULE 2 – Details of Plant Being Offered - 550 kV Current Transformers (1 Amp Secondary Cores)
Item
Particulars Unit CT Type CT Type
No.
CURRENT TRANSFORMERS 4000/3000/2500/1 (50 kA) 4000/3000/2500/1 (63 kA)
1 Name of Maker

2 Country of Manufacture

3 Type Designation or Type Number of CT

4 Type (Dead Tank, Live Tank, Post Type, Bushing Type,

and Oil or SF6 filled)

Dimensions, Weight.
5 Overall dimensions of complete unit:
• Width mm
• Depth mm
• Height mm

• Total weight (incl. oil/SF6) kg

6.1 Quantity of Oil required for each Current Transformer Litres

assembly

6.2 Quantity of SF6 required for each CT assembly (at kg

normal operating pressure)

7 Method of Shipping and Transport (full details to be

included with Tender)

8 Dielectric Dissipation Factor of Oil at 20 ºC and 90ºC Radians

(maximum value)

9 Resistivity of Oil at 20 ºC and 90 ºC (minimum value) Ohm-cm

10 Dielectric Strength of Oil kV

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Item
Particulars Unit CT Type CT Type
No.
11 Type of Material used for secondary terminals/ bushings
(conductor stud and the means adopted to prevent oil or
SF6 leakage)

12 Conductor Material used in secondary windings

13 What type of Insulation is used on the secondary

winding wire?

14 Is there an earth shield between the high voltage

conductor and the secondary windings?

15 Effective length of primary bushing between metallic mm

attachment devices

16 Effective creepage distance along bushing. mm

17 Is external Spark Gap required to coordinate Insulation

(Post type CT)

18 If answer to 17 is Yes, what is recommended gap mm

setting?

19 For Post type CT, what is Capacitance and the Dielectric

Dissipation Factor for:
• Primary to Capacitance Tap?
• Secondaries to Capacitance Tap?
Primary to Remainder?

20 Type of Insulator Shell (If polymer, please provide Years

details), and estimated service life.

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Item
Particulars Unit CT Type CT Type
No.

CURRENT TRANSFORMERS 4000/3000/2500/1 (50 kA) 4000/3000/2500/1 (63 kA)

21 Name of Testing Authority, place at which
following Tests will be carried out.
• Type Tests?
• Routine Tests?

22 Type of Material in Oil Expansion bellows. (If

applicable)

Voltage Tap (If Applicable)

23 Voltage of Intermediate Voltage Tap kV rms.

24 Output Burden after Electromagnetic Unit

25 Required condition of Intermediate Voltage Tap Earthed/

when not in use.
Unearthed

CT Marshalling Box
26 Degree of weather protection

27 Maker

Oil or SF6 Level Indication

28 Method of indicating level of nitrogen Provide details

pressurisation (oil filled CTs)

29 Type of Gas Density Monitor or monitors Provide details

provided (SF6 filled CTs)

30 Guaranteed SF6 leakage rate (If applicable) %

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SCHEDULE 3: Information to be supplied by Respondents

Documents/Manuals List Schedule

The Tenderer must supply four complete sets of instruction manuals for each different voltage
rating Capacitor Voltage Transformer to be supplied. These must cover the correct assembly,
erection, operation, maintenance and repair of the Plant, having regard to the class of employee
who may reasonably be expected to be supervising and carrying out these several Works. A
draft copy of any generic instruction manual must be supplied with the Request for Tender.

The instructions must be bound in a durable cover suitable for use on-Site and the front clearly
marked with SP AusNet's Invitation to Tender Number, Contract Number, and a brief plant
description. An electronic pdf version must also be supplied.

For the purposes of the tender evaluation the Tenderer must identify the documentation(s) in
which this information will be supplied in the “Document/Manual Title and Version” column of the
following table. SP AusNet reserves the right to request copies of these documents to facilitate
tender evaluation. While generic manuals are usually supplied with this plant, the manual must
include sufficient additional documentation to allow the manual to be referenced to the specific
plant. This includes name and rating plate details, serial numbers, request for tender numbers,
order numbers and the voltage ratio, accuracy and burden details. Sufficient details must be
included to permit spare parts to be ordered without confusion.

Description Document/Manual Title and

Version

Plant packing, Un-packing, Assembly, Lifting, Moving,

Erection and Commissioning procedures.

Operation description. Including checking the condition

of any bellows/diaphragm.

General arrangements showing wiring of CTs and

secondary terminal boxes.
Major component replacement and overhaul procedures.

Spare parts lists.

Primary and secondary termination details.

Dimensions and foundation mounting details.

Data sheet on any insulating medium such as oil and
SF6 gas, type and handling and safety considerations.

Dimensions and weight of each CT Type.

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Drawings List Schedule

As a minimum the following drawings, to the extent they are not inconsistent with the Technical
Standard, will form part of the description of the plant to be supplied and the Work to be carried
out.

The Tenderer is to provide a listing of the applicable drawings and supply a copy of each with its
tender. SP AusNet reserves the right to request copies of these documents to facilitate tender
evaluation.

Description Drawing Number

General Arrangement of the Plant showing all the main
dimensions, and weight

General Outline drawing of the complete Current Transformer

arrangement

Internal arrangements of the Current Transformer showing the

assembly and connection of the, including the method of
locating cores. .

Name and Rating Plates.

Cross sectional drawings of the Current Transformers
General connection drawing of the enclosing porcelain showing
the general arrangement and method of clamping of cores.
Details of High Voltage Connection Terminal.

Type Test Index Schedule

All performance values must be supported by type test data. Tests must be carried out in
accordance with this Technical Standard, and the relevant standards. Where type test data
does not exist for the item offered, test on equivalent items will be considered only if details of
similarities and differences and a justification of relevant equivalence for equipment and test
layout are provided.

The Tenderer is to complete the following tables with the applicable report reference and
comments (where applicable).

Tenderers must submit complete type test reports, supplementary information and the type test
index for the items listed below with their tender. This requirement is a necessary preliminary to
the acceptance by SP AusNet of any tender.

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Outdoor Current Transformers –Equipment Specification

Technical AS 60044.5 Type Tests Report Comments e.g.,

Standard Reference Equipment tested (if
Clause
Clause different than offered
Reference
Reference equipment
designation)

Standard Type Tests

7.1 Short Time & Peak Current

Withstand Test

7.2 Temperature Rise Test

7.3 Lightning & Switching -

Impulse

7.4 Wet Dielectric Test

7.5 Radio Interference Test

11.4, 12.4, 11.6, Determination of Error

12.5, 14.3 Checks

Special Type Tests

5.7.4 9.1 Chopped Impulse Test
5.7.4 Annex B Multiple Chopped impulse
tests

5.7.4 ‘Safe’ Failure mode tests

5.7.4 - Secondary Open Circuit

Induced High Voltage Test

Routine Test Index Schedule

Routine tests must be carried out in accordance with this Technical Standard, and the relevant
standards. The Tenderer must identify the routine tests that will be carried out on the each item
of plant, and the documentation in his offer that details the test, in the following table.
Technical AS60044.5 Description of Test Description of Test Tenderer’s
Standard Clause that Tenderer will Comments
Clause Reference provide.
Reference

Standard Routine Tests

8.1 Verification of Terminal

markings and nameplates

8.2 Power Frequency Withstand

and Partial Discharge
Measurement on primary
windings

8.3 & 14.4 Power Frequency Withstand

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Tests on secondary windings

8.4 & 5.1.5 Inter-turn Overvoltage Test

11.5, 12.4, 12.6 Determination of Errors-

& 14.4 Routine Tests for PX
protective current transformers

Special Routine Tests

- Lightening impulse withstand

voltage on primary insulation

5.8.3 - Over voltage test on protective

devices

5.8.3 9.2 Capacitance and Dielectric

Dissipation Factor

5.8.3 14.4.1 Performance test on protection

cores

5.8.3 11.4 Performance test on metering

core

5.8.3 Oil Quality analysis

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Schedule 4: Technical Requirements Compliance Schedule

The following table allows the Tenderer to indicate either compliance with the Technical
Requirements of this Request for Tender or alternatively highlight any non-compliance

Tenderers warrant that the tenderers offered equipment complies with the SP AusNet
C (Complies) indicates that the supplier’s offer is completely in accordance with the clause.

DNC (Does Not Comply) indicates that the offered equipment:

• does not comply with the requirements of the clause;
• only partially complies with the requirements of the clause; or
• only complies with the requirements of the clause to the extent clarified or qualified in the
“Comments” column.
The Tenderer must only insert comments where compliance is stated as DNC (Does not
Comply). Notwithstanding this, the supplier is deemed to be offering 100% compliance to the
requirements of a clause where compliance is stated as a C (Complies), regardless of any
comment inserted against that clause.

Technical Requirements Clause C / DNC Comments, if non-

compliant
3 General Requirements
3.2 Climatic conditions

5.0 Technical requirements

5.1 General CT Requirements
5.1.1 Insulator Housing
5.1.2 Creepage Distance
5.1.3 Terminals
5.2 Construction

5.2.1 Quality
5.2.2 Bolts

5.2.3 Locking
5.2.4 Insulating Liquid
5.2.5 Oil sampling and filling

5.2.6 Oil level & Nitrogen pressure indicators

5.2.7 SF6 density monitors

5.2.8 Solid insulating material

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5.2.9 Painting and preservation
5.2.10 Special environmental: toxicology safety
5.2.11 Secondary winding design

5.2.12 Protective devices to prevent secondary winding

flashover
5.2.13 Polarities
5.2.14 Support structures
5.2.15 Marshalling boxes
5.3 Terminating boxes ,connections ,terminal markings

5.4 Earthing
5.5 Rating Plates
5.6 Testing
5.7 Type Tests
5.7.2 Standard Type Tests
5.7.3 Special requirements for type tests
5.7.4 Special Type Tests
5.8 Routine Tests
5.8.1 Standard Routine Tests
5.8.2 Special requirements for routine tests
5.8.3 Special Routine Tests
5.9 Tests after delivery

6.0 Safety Requirements

6.1 Insulator housing
6.2 Insulator liquid
6.3 Oil sampling and filling
6.4 Oil level indication and Nitrogen pressure indication
6.5 Special environmental: toxicology Safety

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