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OLTC Test

This document provides testing guidelines for verifying the operation of an on-load tap changer (OLTC) under various transformer conditions, including unenergized, unloaded, loaded, and reduced conditions. It outlines the purpose, scope, responsibilities, equipment needed, safety requirements, and test instructions for performing tests on the OLTC. The tests include operating the tap changer through its full range with the transformer unenergized, operating it at reduced voltage, operating it during no-load energized conditions, and operating it during loaded conditions.

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446 views3 pages

OLTC Test

This document provides testing guidelines for verifying the operation of an on-load tap changer (OLTC) under various transformer conditions, including unenergized, unloaded, loaded, and reduced conditions. It outlines the purpose, scope, responsibilities, equipment needed, safety requirements, and test instructions for performing tests on the OLTC. The tests include operating the tap changer through its full range with the transformer unenergized, operating it at reduced voltage, operating it during no-load energized conditions, and operating it during loaded conditions.

Uploaded by

mshahidshaukat
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Department/Section: Module No: Issuance Date:

HV Transformer/I & QC

Issued By: Work Instruction No.: Superseding Date: WI-I&QC-07

TESTS ON OLTC

02 01 REV Date Prepared By Name Department Designation Signature Abdul Rehman I & QC Engineer Name Department Designation Signature Checked By Raza Aftab/Muhammad Shafiq I & QC Sr. Engineer/ Test Field Engineer Nature of Change Approved & Controlled By Name Department Designation Signature Jahanzeb Ahmad I & QC Manager

Note: Copying of this document is strictly forbidden. Proprietary data. Company confidential. All rights reserved.

TESTS ON ON-LOAD TAP CHANGER


WORK INSTRUCTION WI-I&QC-07 Revision: 00 Page 2 of 3

1.0

PURPOSE The purpose of this document is to provide guidelines to the Testing Engineer to verify the operation of the on-load tap changer at various conditions of the transformer i.e. unenergized, unloaded, loaded & reduced conditions.

2.0

SCOPE This instruction applies to the in-house & final testing of the HV Transformer.

3.0

RECORDS NIL

4.0

ASSOCIATED DOCUMENTS The standard applicable for this test is IEC 60076-1.

5.0

DEFINITIONS On-Load Tap Changer A device for changing the tapping connections of a winding, suitable for operation while the transformer is energized or on load.

6.0

RESPONSIBILITY Test will be performed under the supervision of Testing Engineer/Sub Engineer of I & QC section of HV Transformer department.

7.0

EQUIPMENTS/INSTRUMENTS Following equipments/instruments are required to perform this test: 1. 2. 3. 4. 5. 6. Motor Generator set, 375/750 kVA, 800 A, 415 V, 50/100/150 Hz. Step-up Adaptor Transformer, 3000 kVA, 415 V/ 1 23 kV. Power Analyzer WT3000 Yokogawa-Japan / Norma-USA / equivalent. Current Transformers, 400/1 A. Potential Transformers, 25 kV/110 V. Compensation Capacitors, (Bank Capacity 2700 KVAR).

8.0

MEASURING CIRCUIT NIL

TESTS ON ON-LOAD TAP CHANGER


WORK INSTRUCTION WI-I&QC-07 Revision: 00 Page 3 of 3

9.0

SAFETY REQUIREMENTS 1. All connections should be tight. 2. Proper clearances should be observed. 3. Proper alignment between the tap changer indicator and the motor drive indicator should be ascertained.

10.0

INSTRUCTIONS With the tap changer fully assembled on the transformer the following sequence of operations shall be performed without failure. a. With the transformer un-energized, eight complete cycles of operation (a cycle of operation goes from one end of the tapping range to the other, and back again). b. With the transformer un-energized, and with the auxiliary voltage reduced to 85% of its rated value, one complete cycle of operation. c. With the transformer energized at rated voltage and frequency at no load, one complete cycle of operation. This test may be performed after performing the no load test. d. With one winding short circuited and, as far as practicable, rated current in the tapped winding, 10 tap change operations across the range of two steps on each side from where a coarse or reversing changeover selector operates, or otherwise from the middle tapping.

11.0

CALCULATIONS NIL

12.0

TOLERANCES NIL

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