KARNATAKA POWER CORPORATION LTD.

370MW YELAHANKA CCPP

VOLUME – II

TECHNICAL SPECIFICATION FOR

OIL FILLED SERVICE TRANSFORMERS

SPECIFICATION NO : PE-TS-409-302-E001
REV-0

BHARAT HEAVY ELECTRICALS LIMITED

POWER SECTOR
PROJECT ENGINEERING MANAGEMENT
NOIDA, UTTAR PRADESH, INDIA – 201301
 SPECIFICATION NO. PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR
VOLUME II
OIL FILLED SERVICE TRANSFORMERS
CONTENTS SHEET
REVISION 0 DATE: 14.06.2016
370MW YELAHANKA CCPP
SHEET 1 OF 1

CONTENTS

S. NO. CONTENTS NO. OF SHEETS

01 COMPLIANCE CERTIFICATE 01

02 SECTION - ‘I’ SPECIFIC TECHNICAL REQUIREMENT 19

ANNEXURE-I (DOCUMENTS REQUIRED

ALONG WITH TECHNICAL OFFER) (01)

ANNEXURE -II (DOCUMENTS REQUIRED

AFTER AWARD OF LOI) (02)

ANNEXURE -III (LIST OF TYPE TESTS) (01)

ANNEXURE -IV (SPECIAL TOOLS AND TACKLES

REQUIRED FOR ERECTION, COMMISSIONING
AND MAINTENANCE OF EQUIPMENT) (01)

ANNEXURE -V (COMMISSIONING SPARES

FOR EACH TRANSFORMER) (01)

DATA SHEET-A (04)

DATA SHEET-B (01)

DATA SHEET-C (06)

03 SECTION - ‘II’ STANDARD TECHNICAL SPECIFICATION 30

TOTAL NUMBER OF SHEETS: 50

 SPECIFICATION NO. PE-TS-409-302-E001

TECHNICAL SPECIFICATION FOR VOLUME-II

OIL FILLED SERVICE TRANSFORMER COMPLIANCE CERTIFICATE
REVISION 00 DATE: 14.06.2016

COMPLIANCE CERTIFICATE

The bidder shall confirm compliance to the following by signing/ stamping this compliance certificate and
furnishing same with the offer.

1. The scope of supply, technical details, construction features, design parameters etc. shall be as per
technical specification & there are no exclusion/ deviation with regard to same

2. There are no deviation with respect to specification other than those furnished in the ‘schedule of
deviations’

3. Only those technical submittals which are specifically asked for in NIT to be submitted at tender stage
shall be considered as part of offer. Any other submission, even if made, shall not be considered as part of
offer.

4. Any comments/ clarifications on technical/ inspection requirements furnished as part of bidder’s covering
letter shall not be considered by BHEL, and bidder’s offer shall be construed to be in conformance with the
specification.

5. Any changes made by the bidder in the price schedule with respect to the description/ quantities from those
given in ‘BOQ-Cum-Price schedule’ of the specification shall not be considered (i.e., technical description
& quantities as per the specification shall prevail).

---------------------------------------------------------------------
BIDDER’S STAMP & SIGNATURE
 SECTION ‘I’

SPECIFIC TECHNICAL
REQUIREMENTS
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 2 of 19 

 
1.0 SCOPE OF ENQUIRY

1.1 This specification covers the design, manufacture, inspection and testing at manufacturer's
works, proper packing and delivery to site of BIS certified OIL FILLED SERVICE
TRANSFORMERS (BIS Certification for rating upto 2.5 MVA, 33kV Class as per IS-1180
part-1, however the impedance value, list of tests, fittings shall be as per those mentioned in
the specification) as mentioned in different sections of this specification, complete with all
accessories for efficient and trouble-free operation.

1.2 It is not the intent to specify herein all the details of design & manufacture. However, the
equipment shall conform in all respect to high standards of design engineering and
workmanship and shall be capable of performing in continuous commercial operation.

1.3 Standard technical requirements of the oil filled service transformers are indicated in Section-
II. Project specific requirements/changes are listed in Section-I.

1.4 The requirements of Section-I shall prevail and govern in case of conflict between the
corresponding requirements of Section-I and Section-II.
 
 
2.0 BILL OF QUANTITIES:

2.1 Quantity requirements shall be as per BOQ-cum-price schedule as part of NIT.

3.0 SPECIFIC TECHNICAL REQUIREMENTS

S.No. Reference Clause No. of Specific Requirement/ Change

Section- II

NIL NIL

4.0 DOCUMENTATION
4.1 Documents required along with technical offer shall be as per annexure-I.
4.2 Documents required after award of LOI shall be as per annexure -II.
 
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 3 of 19 

 
ANNEXURE – I

DOCUMENTS REQUIRED ALONG WITH TECHNICAL OFFER 

a) The enclosed Data Sheet-B filled up completely for each rating/ type of transformers.

b) Schedule of deviations.

c) Schedule of BOQ cum price schedule. (Unpriced)

d) 10% Extra oil price schedule (Unpriced)

e) Schedule of Mandatory spares. (Unpriced)

f) Schedule of Type test. (Unpriced)

g) List of special tools and tackles required for erection, commissioning and maintenance of
equipment as per annexure-IV of section-I, volume-II.

h) List commissioning spares for each transformer as per annexure-IV of section-I, volume-II.
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 4 of 19 

 
ANNEXURE – II

DOCUMENTS REQUIRED AFTER AWARD OF LOI

Sl No  DrawingNO  Drg Title 

1  PE‐V0‐409‐302‐E802  SERVICE TRANSFORMER O & M MANUAL                                                 
1600KVA TRANSFORMER (6.6/0.433KV) LV BUS DUCT TRUNKING 
2  PE‐V0‐409‐302‐E147 
DRAWING                               
3  PE‐V0‐409‐302‐E149  1600KVA TRANSFORMER (6.6/0.433KV) L.V. BUSHING                          
4  PE‐V0‐409‐302‐E150  1600KVA TRANSFORMER (6.6/0.433KV) LVN BUSHING                          
5  PE‐V0‐409‐302‐E805  SERVICE TRANSFORMER TYPE TEST REPORTS                                          
1600 KVA SERVICE TRANSFORMER (6.6/0.433KV) OUTLINE 
6  PE‐V0‐409‐302‐E142 
GENERAL ARRANGEMENT DRAWING [OGA]                                             
7  PE‐V0‐409‐302‐E144  1600KVA TRANSFORMER (6.6/0.433KV) FOUNDATION PLAN               
1600KVA TRANSFORMER (6.6/0.433KV) GENERAL ARRANGEMENT 
8  PE‐V0‐409‐302‐E145 
OF MARSHALLING BOX                                                                              
9  PE‐V0‐409‐302‐E151  1600KVA TRANSFORMER (6.6/0.433KV) VALVE SCHEDULE PLATE       
1600KVA TRANSFORMER (6.6/0.433KV) WIRING DIAGRAM FOR 
10  PE‐V0‐409‐302‐E152 
MARSHALLING BOX                                                                                
1600 KVA SERVICE TRANSFORMER (6.6/0.433KV) TECHNICAL DATA 
11  PE‐V0‐409‐302‐E141 
SHEET                                                                                  
12  PE‐V0‐409‐302‐E803  SERVICE TRANSFORMER PAINTING PROCEDURE                                     
1600 KVA SERVICE TRANSFORMER (6.6/0.433KV) RATING & 
13  PE‐V0‐409‐302‐E143 
DIAGRAM PLATE 
14  PE‐V0‐409‐302‐E148  1600KVA TRANSFORMER (6.6/0.433KV) H.V. BUSHING                         
1600KVA TRANSFORMER (6.6/0.433KV) HV CABLE BOX 
15  PE‐V0‐409‐302‐E146 
ARRANGEMENT DRAWING                                                                          
16  PE‐V0‐409‐302‐E801  SERVICE TRANSFORMER FIELD QUALITY PLAN                                         
17  PE‐V0‐409‐302‐E901  QUALITY PLAN FOR SERVICE TRANSFORMERS                                         
1600KVA TRANSFORMER (6.6/0.433KV) DESIGN CALCULATIONS 
18  PE‐V0‐409‐302‐E155 
FOR SHORT CIRCUIT CAPABILITY                                                                 
1600KVA TRANSFORMER (6.6/0.433KV) TRANSPORTATION 
19  PE‐V0‐409‐302‐E153 
DETAILS                                                                                      
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 5 of 19 

 
PE-V0-409-302-E175 2000KVA TRANSFORMER (6.6/0.433KV) DESIGN CALCULATIONS
20  FOR SHORT CIRCUIT CAPABILITY

PE-V0-409-302-E168 2000KVA TRANSFORMER (6.6/0.433KV) H.V. BUSHING

21 

PE-V0-409-302-E170 2000KVA TRANSFORMER (6.6/0.433KV) LVN BUSHING

22 

PE-V0-409-302-E165 2000KVA TRANSFORMER (6.6/0.433KV) GENERAL ARRANGEMENT

23  OF MARSHALLING BOX

PE-V0-409-302-E166 2000KVA TRANSFORMER (6.6/0.433KV) HV CABLE BOX

24  ARRANGEMENT DRAWING

PE-V0-409-302-E173 2000KVA TRANSFORMER (6.6/0.433KV) TRANSPORTATION

25  DETAILS

PE-V0-409-302-E172 2000KVA TRANSFORMER (6.6/0.433KV) WIRING DIAGRAM FOR

26  MARSHALLING BOX

PE-V0-409-302-E164 2000KVA TRANSFORMER (6.6/0.433KV) FOUNDATION PLAN

27 

PE-V0-409-302-E171 2000KVA TRANSFORMER (6.6/0.433KV) VALVE SCHEDULE PLATE

28 

PE-V0-409-302-E169 2000KVA TRANSFORMER (6.6/0.433KV) L.V. BUSHING

29 

PE-V0-409-302-E167 2000KVA TRANSFORMER (6.6/0.433KV) LV BUS DUCT TRUNKING

30  DRAWING
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 6 of 19 

 
ANNEXURE – III
LIST OF TYPE TESTS

Sl No TYPE TEST
1 TANK PRESSURE TEST
2 TANK VACUUM TEST
3 MEASUREMENT OF ACOUSTIC NOISE LEVEL AS PER NEMA TR-1
4 TEMPERATURE RISE TEST
5 DIELECTRIC TYPE TEST (INCLUDING CHOPPED WAVE IMPULSE TEST)
6 SHORT CIRCUIT TEST **
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 7 of 19 

 
ANNEXURE IV

SPECIAL TOOLS AND TACKLES REQUIRED FOR ERECTION, COMMISSIONING

AND MAINTENANCE OF EQUIPMENT

S. NO. DESCRIPTION QTY.

Note

Bidder shall furnish the list of special tools & tackles and quantity along with the offer. Price shall
be included in the total bid price.
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 8 of 19 

 
ANNEXURE -V

COMMISSIONING SPARES FOR EACH TRANSFORMER

S. NO. DESCRIPTION QTY. REMARKS

1600 kVA 2000 kVA

Note

Bidder shall furnish the list of commissioning spares and quantity for each type of transformer along
with the offer. Price shall be included in the transformer price.
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 9 of 19 

 
DATA SHEET –A

6.6/0.433kV SERVICE TRANSFORMER

S. No. Description Unit Particulars

1.0 Quantity Nos. & kVA 12 & 1600 kVA

2 & 2000 kVA

2.0 Installation Out Door

3.0 Type of insulating oil Mineral

4.0 No. of phase No(s) 03

5.0 Frequency Hz 50

6.0 Type of cooling ONAN

7.0 Rated Voltage

a) HV Winding kV 6.6
b) LV Winding kV 0.433

8.0 No Load transformation ratio 6.6/0.433

9.0 Vector group Dyn1

10.0 Impedance voltage at rated current and frequency % 1600 kVA : 8%

2000 kVA : 10%

11.0 Total range of tapping’s and tapping steps + 5% in steps of 2.5%

12.0 Type of tap changing equipment Off-Circuit

`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 10 of 19 

 
13.0 Temperature rise
a) Top oil by thermometer deg. C 50 deg. C above
ambient of 50 deg.C
b) Winding by resistance deg. C 55 deg. C above
ambient of 50 deg.C
14.0 System Highest Voltage
a) HV Winding kV 7.2 kV
b) LV Winding V 415V + 10%

15.0 Phase Connection

a) HV Winding Delta
b) LV Winding Star

16.0 Insulation Levels

16.1 One minute power frequency withstand voltage

a) HV Winding kV 20 (6.6kV)

b) LV Winding kV 3

16.2 Impulse withstand voltage

a) HV Winding kVp 60 (6.6kV)

b) LV Winding kVp -

17.0 Terminal details

a) HV Line Cable box (XLPE cables)
b) HV Neutral N.A.
c) LV Line Flange throat for TPN non-
segregated Al Busduct

d) LV Neutral One neutral as part of LV busduct

throat and second neutral with
copper earthing bar for system
earthing brought near the base of
the transformer.
18.0 System Fault Level
a) HV Winding kA 40 kA RMS
b) LV Winding kA 50 kA RMS
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 11 of 19 

 
19.0 Method of System Earthing
a) HV System low resistance earthed to limit
earth fault current to 300A
b) LV System Solidly grounded
c) Through fault withstand time 2 Sec.

20.0 Details of Cooling Equipment Detachable tank mounted radiators

21.0 Provision/ accommodation of CTs

LV Neutral 2 Core PS CLASS or 5P20.
CT particulars shall be given to
successful bidder during detail
engineering. There shall be no
commercial implication to BHEL on
this account.

22.0 Colour Shade :

a) Interior (For M. Box) Particulars shall be given to
successful bidder during detail
engineering. There shall be no
commercial implication to BHEL
on this account.

b) Exterior Particulars shall be given to

successful bidder during detail
engineering. There shall be no
commercial implication to BHEL
on this account.

23.0 Space/ Layout Limitation if Any

24.0 Cable details

a) HV side
i) Type XLPE
ii) Voltage Grade 6.6kV Unearthed
iii) Conductor material & size Stranded Aluminium,
after award of contract
iv) No. of cores & runs Three core, one run
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 12 of 19 

 
b) LV side
i) Type N.A
ii) Voltage Grade kV N.A
iii) Conductor material & size N.A
iv) No. of cores & runs N.A

25.0 Penalty for Losses

a) Rates for bid evalution N.A.
b) ‘A’ (for no load loss) Losses not to exceed max.
losses as per annexure-B to
section-II, vol-II of the
specification
ii) ‘B’ (for load losses) - Do-

c) Rates for penalty

i) ‘A’ (for no load loss) As per NIT
ii) ‘B’ (for load loss) As per NIT

28.0 Creepage distance 25mm/kV

29.00 Painting Procedure As per IS-1180

[Mention Thermo Setting powder/ Epoxy paint]
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 13 of 19 

DATA SHEET –B

TECHNICAL PARTICULARS
[TO BE SUBMITTED ALOGWITH TECHNICAL OFFER]

FOR 6.6kV/0.433V
S. No Description 1.6MVA
1. Rating
2. No Load
transformation ratio
3. Maximum No- load
losses at rated
frequency and 100%
rated voltage
4. Maximum load losses
at normal ratio, rated
current and 75 deg. C
5. Overall Dimensions
6. Total weight
7. Total oil Quantity
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 14 of 19 

DATA SHEET –C

TECHNICAL PARTICULARS
[TO BE SUBMITTED AFTER AWARD OF CONTRACT]

S. No. Description Unit Particulars

1.0 Name of Manufacturer

2.0 Reference Standards

3.0 Installation

4.0 Rated no load Voltage

a) HV Winding kV
b) LV Winding kV

5.0 Type of cooling

6.0 Rated kVA

7.0 No. of phase No(s)

8.0 Rated Frequency Hz

9.0 Winding connections

a) HV Winding
b) LV Winding

10.0 Vector group

11.0 Impedance voltage at rated current and frequency %

for the principal tapping at 75 deg. C

12.0 Off-Circuit tap changer

a) Total range of tappings (+/-) %
b) Size of tapping step %
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 15 of 19 

 
c) For HV/LV variation

13.0 Impulse voltage withstand level

a) HV Winding kVp
b) LV Winding kVp

14.0 Power frequency withstand voltage for one minute

a) HV Winding kV
b) LV Winding kV

15.0 Maximum No load losses at rated frequency and

a) 100% rated voltage kW
b) 110% rated voltage kW

16.0 Maximum Load losses at normal ratio, rated current

and 75 deg. C

17.0 Tolerance on losses (+/-)

18.0 Guaranteed maximum Temperature rise of

a) Top oil by thermometer deg. C
above ambient of 50 deg. C

b) Winding by resistance deg. C

above ambient of 50 deg. C

19.0 Efficiency at 75 deg. C and unity power factor for

a) 100% full load %
b) 75% full load %
c) 50% full load %

20.0 Voltage regulation at full load at 75 deg. C

a) Unity power factor %
b) 0.8 Power factor (Lagging) %

21.0 External short circuit withstand capacity & duration MVA, sec

22.0 Max. short time (30 sec.) rating of transformer KVA

23.0 Type of magnetic circuit Core/ Shell

24.0 Type of core joints

`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 16 of 19 

25.0 Type of winding

a) HV Winding
b) LV Winding

26.0 Type of insulation

a) HV winding
b) LV winding
c) Between core & adjacent winding
d) Between windings

27.0 HV terminal arrangement

a) Bushing with or without CTs
b) CT details (Ratio, ACC. Class, VA, Type)
c) Clearance between phases in air mm
d) Clearances to earth in air mm

28.0 LV terminal arrangement

a) Bushing with or without CTs
b) CT details (Ratio, ACC. Class, VA, Type)
c) Clearance between phases in air mm
d) Clearances to earth in air mm

29.0 Neutral terminal arrangement

a) No. of neutral terminals
b) Neutral CT provided or not
c) NCT details (Ratio, ACC. Class, VA, Type)

30.0 HV Bushing
a) Rated voltage class kV
b) Rated current A

31.0 LV Bushing
a) Rated voltage class kV
b) Rated current A

32.0 LV Neutral Bushing

a) Rated voltage class kV
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 17 of 19 

 
b) Rated current A

33.0 Maximum flux density

a) At rated voltage Wb/M2
b) At 110% rated voltage Wb/M2
34.0 Maximum current density for
a) HV Winding Amp/mm2
b) LV Winding Amp/mm2

35.0 Magnetising current at rated voltage and

frequency (% of full load current)

36.0 Rollers
a) Type
b) Unidirectional/ Bidirectional
c) Quantity
d) Gauges
i) Longitudinal mm
ii) Transverse mm

37.0 Pressure test withstand

a) Tank Kg/M2
b) Radiator and other fittings Kg/M2

38.0 Vacuum withstand

a) Tank mm of Hg
b) Radiator and other fittings mm of Hg

39.0 Approximate weight of

a) Core Kg
b) Windings Kg
c) Tank, Fittings & Coolers etc. Kg
d) Oil Kg
e) Total weight with oil Kg
f) Untanking weight (core & winding) Kg
g) Shipping weight of the heaviest package Kg

40.0 Quantity of Insulating Oil

a) Oil in tank Ltrs.
b) Oil in cooling equipment Ltrs.
c) Total oil Quantity Ltrs.
41.0 Dimensions
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 18 of 19 

42.1 Tank dimensions

a) Length mm
b) Breath mm
c) Height mm
42.2 Shipping dimensions of the largest package
a) Length mm
b) Breath mm
c) Height mm

42.3 Overall Dimensions (LxBxH) (mmXmmXmm)

43.0 Details of tank and other material

a) Thickness of tank side plate mm
b) Thickness of tank bottom plate mm
c) Thickness of tank cover plate mm
d) Thickness of radiator sheets mm
e) Minimum clearance height for lifting core mm
and winding from tank

44.0 Positive sequence impedance at

a) Maximum voltage tap %
b) Minimum voltage tap %

45.0 Zero-sequence impedance at principal tap %

46.0 Paint Shade :

47.0 Voltage Variation : CFVV

48.0 Noise Level :

49.0 Degree of Protection

a) Marshalling Box : IP55
b) HV Cable Box : IP55
c) LV Flange Enclosure : IP55

50.0 Creepage Distance

a) HV Bushing (mm/kV) :
b) LV Bushing (mm/kV) :
c) Neutral Bushing (mm/kV) :
`   
 TITLE  :  SPECIFICATION NO.
PE-TS-409-302-E001
TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   I 
  REV NO. : 00 DATE : 14/06/2015

SHEET : 19 of 19 

 
51.0 Material of Winding
a) HV/LV :

52.0 Insulation level separate source

power frequency voltage withstand
h) HV winding (kV RMS) :
ii) LV winding (kV RMS) :
iii) HV Bushing :
iv) LV Bushing :
v) Neutral Winding :

53.0 Temperature Class of Insulation :

54.0 Over Excitation withstand time (sec)

100% :
110% :
125% :
140% :

55.0 Thermal Time constant :

56.0 Magnetizing Inrush Current :

57.0 Radiator Details

a) No. of Radiators :
b) No. of Flutes :
c) Overall Dimensions :
d) Radiator sizing calculations furnished : (YES/NO)
 SECTION ‘II’

STANDARD TECHNICAL
SPECIFICATION
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 2 of 30 

 
1.00.00 SCOPE

1.01.00 This specification covers the design, manufacture, inspection & testing, packing at
manufacturer’s works and delivery to site of mineral oil filled service Transformers
complete with all fittings & accessories for satisfactory operation at site.

1.02.00 TERMINAL POINTS

1.02.01 HV bushings with terminal connector for bus duct/ cable glands & lugs in case of
cable connection.

1.02.02 LV bushings with terminal connector (3 Phase + 1 Neutral) for bus duct/ cable glands
& lugs in case of cable connection.

1.02.03 For HV Earthing : (Applicable in case of star connection of HV) - neutral earth
busbar brought near the base of transformer/ Cable glands & lugs in case of cable
connection.

1.02.04 For LV Earthing : - neutral earth busbar brought near the base of transformer/ Cable
glands & lugs in case of cable connection

1.02.05 Transformer earthing pads.

1.02.06 Terminals of marshalling box for external connection to equipment supplied by the
purchaser.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 3 of 30 

 
2.00.00 CODES AND STANDARDS

S.NO. STANDARD NUMBER STANDARD TITLE

1 IS:2026 POWER TRANSFORMERS
IEC: 60076
2 IS:1180 OUTDOOR TYPE OIL IMMERSED DISTRIBUTION
TRANSFORMERS UPTO AND INCLUDING 2500 kVA,
33kV - SPECIFICATION
2 IS:6600 GUIDE FOR LOADING OF OIL IMMERSED
TRANSFORMER
3 IS: 3639 FITTINGS & ACCESSORIES FOR POWER TRANSFORMER

4 IS: 335 NEW INSULATING OILS

IEC: 60296
5 IS: 2099 Bushing for alternative voltage above 1000 volts
IEC: 60137
6 IS: 3347 Dimension for porcelain transformer bushings
7 IS: 2705 Current transformers
IEC: 60185
8 IS: 3637 Gas operated relays
9 IS:1271 Classification of insulating material for electrical machinery &
IEC: 60216 apparatus in relation to their thermal stability in service
10 IS/IEC: 60529 Classification of degrees of protection provided by enclosures of
electrical equipment
11 IS: 2071 Method of high voltage testing
IEC: 60060
12 IS: 5 Colours for ready mixed paints & enamels
13 NEMA, STANDARD-TR1 Noise level
14 CBIP Publication Manual on transformers
(latest edition)

2.01.00 The equipment shall comply with all currently applicable safety codes and statutory
regulations of India as well as of the locality where the equipment is to be installed
including Indian Electricity Act, Indian Electricity Rules and Bureau of Indian
Standards.
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 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 4 of 30 

 
3.00.00 TECHNICAL REQUIREMENTS

3.01.00 Technical particulars of transformers are specified in Data Sheet –A of section-I,

volume-II.

3.02.00 All windings shall be fully insulated. Material of the windings shall be electrolytic grade
copper, free from scales and burrs. Winding shall be uniformly insulated.

3.03.00 The core shall be constructed from high grade, non-ageing, cold rolled, grain oriented
silicon steel laminations.

3.04.00 Internal design of transformer shall ensure that air is not trapped in any location.

3.05.00 Nuts, bolts and pins used inside the transformer shall be provided with lock washers &
locknuts

3.06.00 Tank

3.06.01 Under base of tank shall be fixed type.

3.06.02 Tank shall be of welded construction & fabricated from tested quality low carbon steel
of adequate thickness. Tank shields, if provided, shall not resonate at natural frequency
of equipment.

3.06.03 All steel surfaces in contact with insulating oil shall be painted with two coats of heat
resistant oil in soluble insulating varnish.

3.06.04 Auxiliary transformers shall have suitable bi-directional skids, however auxiliary
transformers above 2 MVA shall be provided with four no. of bi-directional
detachable flat rollers. Suitable locking arrangement shall be provided to prevent
accidental movement of transformer.

3.06.05 At least two adequately sized inspection openings, one at the each end of the tank for
easy access to bushings and earth connections & suitable manhole shall be provided.

3.06.06 The main tank body including tap-changer compartment, radiators and coolers shall be
capable of withstanding full vacuum.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 5 of 30 

 
3.06.07 All tank and oil filled compartment shall be tested for oil tightness by being completely
filled with oil of viscosity not greater than that of specified oil at the ambient
temperature and applying pressure equal to the normal pressure plus 35 kN/m2
measured at the base of the tank.

3.07.00 Tank mounting

Tank shall also be provided with lifting lugs and minimum four jacking pads. Rollers
shall be provided with holding clamp plates (04 nos), required hardware and foundation
bolts etc. for each transformer.

3.08.00 Oil preservation

Conservator tank of adequate capacity for expansion of oil from minimum ambient to
100 deg. C shall be provided. The transformers rated 6.3MVA and above shall be
provided with air bag breathing through silica gel breather. For lower rating
transformers with conventional conservator with dry air filling of the space above oil
and connected to silica gel breather shall be provided.

3.09.00 Radiators
The radiators shall be detachable type, mounted on the tank. Each radiator shall be
provided with a drain plug/valve at the bottom, an air release plug at the top, shut off
valve at each point of connection to the tank.

3.10.00 Insulating Oil

As per IS: 335. No external inhibitors are permitted.

3.11.00 All transformers shall be suitable for cable/ busduct termination as indicated in data
sheet-A of section-I, volume-II.
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 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 6 of 30 

 
3.12.00 Bushings/ Insulators

3.12.01 The bushings shall conform to the requirements of IS: 2099 and IS: 3347 and shall
be of porcelain and above 3150A for the LV bushing Epoxy bushing shall also be
acceptable.

3.12.02 For 33kV windings 36kV bushing shall be provided. For 3.3kV, 6.6kV and 11 kV
windings, 17.5kV bushing shall be provided. For 415V windings, 1.1kV bushings
shall be provided.

3.12.03 The porcelain shall not engage directly with hard metal and, wherever necessary,
gaskets shall be interposed between the porcelain and the fitting.

3.12.04 Clamps and fittings of steel or malleable cast iron shall be galvanised.

3.12.05 Where bushing current transformer is provided, the bushing shall be mounted so that
it can be removed and replaced without disturbing the current transformers. CTs shall
be cast resin type & suitable for operation at ambient temperature existing at its
location on the transformer.

3.12.06 Creepage distance shall be as per data sheet-A of section-I, volume-II.

3.12.07 Minimum rated current for bushings shall be as under. However, same shall comply
with IS-2099 and HV/LV system fault current mentioned in Clause No. 20.00 of
Datasheet A of section-I, volume-II:

1) H V Bushing for 33kV

7.5 MVA = 250A
5.0 MVA = 100A
2.0 MVA = 100A

2) H V Bushing for 11kV & 6.6kV

10.0MVA= 1000A
8.0MVA = 1000A
7.5MVA = 800A
6.3MVA = 800A
5.0MVA = 630A
3.5MVA = 250A
2.5 MVA = 250A
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 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 7 of 30 

 
2.0 MVA = 250A
1.6 MVA = 250A
1.0 MVA = 100A
630 kVA = 100A

2) H V Bushing for 3.3kV

2.5 MVA = 630A
2.0 MVA = 500A
1.6 MVA = 400A
1.0 MVA = 250A
630 kVA = 250A

3) L V Bushing for 11kV, 6.6kV & 3.3kV

10.0MVA= 2500A
8.0MVA = 2000A
7.5MVA = 1600A
6.3MVA = 1600A
5.0MVA = 1250A
3.5MVA= 1250A

4) L V Bushing for 433V/420V

2.5 MVA = 4000A
2.0 MVA = 4000A
1.6 MVA = 3150A
1.0 MVA = 2000A
630 kVA = 1000A

3.13.00 Cable Box

3.13.01 A dust tight air insulated type cable box with D.O.P. of IP: 55 shall be provided for
terminating the cables directly of size and type specified in Data sheet-A of section-
I, volume-II. The cable box shall also be provided with a suitable canopy. Suitable
cable glands (double compression type) and lugs shall be provided for cable
termination.

3.13.02 Dimensions of cable box shall be subject to purchaser’s approval.

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 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 8 of 30 

 
3.13.03 Inspection cover for fixed portion of cable box shall be provided. Handles for
lifting cable box shall be provided.

3.13.04 Creepage distance shall be as per data sheet-A of section-I, volume-II.

3.13.05 Provision shall be made for earthing the body of each cable box. Separate earthing
pads shall be provided for this purpose, suitable for bolted connection to galvanised
mild steel flat of size to be specified during contract engineering stage.

3.13.06 Gland plate for single core cable termination shall be of Aluminium.

3.13.07 Cable box(es) shall be provided with suitable air-insulated disconnecting chamber
so that if required, transformer can be removed from its position without
disconnecting the cables in the cable box(es). Independent supporting arrangement
shall be provided for cable box(es) for this purpose. Supporting arrangement shall be
supplied along with required hardware & foundation bolts etc.

3.14.00 Busduct Termination

If LV terminals are specified to be connected by means of a busduct, a flanged throat

or equivalent connection shall be provided to suit purchaser’s busducts. The winding
termination shall be on outdoor type of bushing. Necessary flexibles shall be
provided by purchaser to connect the bushing terminals to the busbars of the busduct.
Details of busduct shall be furnished during detail engineering stage. Degree of
protection of LV busduct flange enclosure shall be IP:55.

3.15.00 Neutral Terminals

Two (2) nos. neutral terminals shall be provided on LV side. One neutral terminal
shall be part of phase connection arrangement busduct throat/ LV cable-box (as
applicable). Other neutral terminal shall be in a separate box and brought to tank
bottom by means of earthing bar of 50x6 mm of copper, supported on porcelain
insulators mounted on transformer tank. The neutral earthing bar brought to the tank
bottom for connection to station earth shall be provided with holes and suitable
connecting hardware. This earthing bar shall have fork type arrangement at the end.
However neutral may be connected to NGR as per system requirement.
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 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 9 of 30 

 
3.16.00 Neutral CT

Bidder to provide neutral bushing CT as per details given in data sheet – A of section-
I, volume-II for restricted earth fault protection or standby earth fault protection. In
case neutral CT is tank mounted, CT box shall be weather proof having D.O.P. IP:
55. The Neutral CT box shall also be provided with a suitable canopy. CTs shall be
cast resin type.
All CTs (except WTI) shall be mounted in the turret of bushings, mounting inside
the tank is not permitted.

3.17.00 Valves

3.17.01 All valves upto and including 50 mm shall be of gun metal or of cast steel. Larger
valves may be of gun metal or may have cast iron bodies with gun metal fittings.

3.17.02 Sampling & drain valves should have zero leakage rate.

3.18.00 Gaskets

3.18.01 Gasket shall be fitted with weather proof, hot oil resistant, rubberized cork.

3.18.02 If gasket is compressible, metallic stops shall be provided to prevent over

compression.

3.18.03 The gaskets shall not deteriorate during the life of transformer/shunt reactor if not
opened for maintenance at site. All joints flanged or welded associated with oil shall
be such that no oil leakage or sweating occurs during the life of transformer.

3.19.00 Voltage control (off circuit type)

3.19.01 Off circuit tap-changing switch shall be three phase, hand operated, for simultaneous
switching of similar taps on all the three phases by operating an external handle/ hand
wheel. The position of off-circuit tap switch handle/hand wheel provided outside the
transformer tank should be such as to enable an operator standing on ground to operate
the same with ease. A caution plate indicating that switch shall be operated only when
the transformer is de-energised shall be fitted near tap switch.
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 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 10 of 30 

 
3.19.02 Operating mechanism of tap changer shall be suitably labelled to show the direction
of operation for raising secondary voltage & vice versa. Position markings shall be
provided.

3.19.03 Arrangement shall be made for securing and padlocking the tap-changing switch at
any working position. It shall not be possible to set and padlock in any intermediate
position.

3.19.04 Tap position indicator and mechanical stops to prevent over-cranking of the
mechanism shall be provided.

3.20.00 Marshalling box

3.20.01 Tank mounted vermin and dust proof marshalling box shall be provided to
accommodate indication circuits and temperature indicators etc. and provided with
proper lighting and thermostatically controlled space heaters.

3.20.02 The marshalling box shall be fabricated using sheet steel of at least 2.5mm thickness.
The marshalling box shall have domed or sloping roof.

3.20.03 Marshalling box shall be complete with all internal wiring and identification ferrules,
cables, conduits required for wiring between marshalling box and instruments on
transformer. Wiring shall be by 1100 V grade, copper cable of size 2.5mm2.
3.20.04 The terminal blocks shall be complete with insulating barriers and clip-on type
terminals suitable for 2.5mm2 stranded copper wire. One dummy terminal block in
between each trip wire terminal shall be provided. At least 20% spare terminals shall
be provided on each panel. The gasket used shall be of neoprene rubber.

3.20.05 The marshalling box shall have IP: 55 degree of protection.

3.20.06 CT terminals shall be with shorting and disconnecting facility. TB shall be stud type
for all CT & power connection.

3.20.07 Wiring scheme shall be engraved in a stainless steel plate with viewable font size and
the same shall be fixed inside the Marshalling Box door. Refer annexure-C for
standard terminal block numbering.
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 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 11 of 30 

 
3.21.00 Flux density

Flux density in any part of the core & yoke on any tap position with 10% voltage
variation from voltage corresponding to the tap shall not exceed 1.9 Wb/m2.
Transformer shall also withstand following conditions due to combined voltage and
frequency variations:
Continuous operation for 110% flux density
At least 1 minute operation for 125% flux density
At least 5 sec. operation for 140% flux density

3.22.00 Winding

For 33kV, 11kV & 3.3kVwinding, type of winding shall be continuous disc & for
433V/ 420V winding, type of winding shall be spiral type. The conductors shall be
of Electrolytic grade copper.

3.23.00 Noise & Vibration

The design and manufacture of transformer, fittings and accessories shall be such as
to reduce noise & vibration. Noise level shall not be more than as specified in NEMA
Standard Publication TR-1, when measured with transformer energised at normal
voltage and frequency.

3.24.00 All transformers and their accessories shall be capable of withstanding without
damage any external short circuit at the terminals for duration of two seconds.

3.25.00 Maximum Transformer losses including tolerances shall be as per annexure – B, of

section-I, volume-II.

3.26.00 LOADING CAPABILITY

Transformer shall be suitable for continuous operation at rated kVA on any tap with
voltage variation of + 10 % corresponding to voltage of the tap. Short duration
overloading shall be in accordance with IS:6600 / IEC60076-7.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 12 of 30 

 
4.00.00 Fittings & accessories

4.01.00 Transformer shall be provided with, but not restricted to following minimum
fittings and accessories for satisfactory operation:

4.01.01 Conventional type conservator with drain valve and oil filling hole.

4.01.02 Magnetic oil level gauge with low-level alarm contact.

4.01.03 Prismatic & toughened glass oil level gauge.

4.01.04 Gaskets

4.01.05 Gasket protection covers.

4.01.06 Silica gel breather with oil seal.

4.01.07 Double float type Buchholz relay with alarm and trip contacts with suitable gas
collecting device with two shut-off valve on both side.

4.01.08 Diaphragm type explosion vent for transformers of rating less than 2MVA

4.01.09 Pocket on tank cover for thermometer.

4.01.10 Protected type mercury in glass thermometer.

4.01.11 Dial type (150 mm) Oil temperature indicator (OTI) with two sets of electrical
potential- free contact rated for 2A, 220V DC, for alarm and trip purpose. The OTI
shall be provided with anti-vibration mounting. OTI shall have maximum reading
pointer along with resetting device. For remote oil temperature metering, an
independent 4-20 mA should be made available.

4.01.12 Dial type (150 mm) Winding temperature indicator (WTI) with two sets of electrical
potential- free contact rated for 2A, 220V DC, for alarm and trip purpose. The WTI
shall be provided with anti-vibration mounting. WTI shall have maximum reading
position along with resetting devices. For remote winding temperature metering, an
independent 4-20 mA should be made available.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 13 of 30 

 
4.01.13 Drain Valves.

4.01.14 Sampling devices.

4.01.15 Filter valves.

4.01.16 Earthing terminals – 2 Nos.

4.01.17 Rating & Diagram plates.

4.01.18 Valve schedule plate.

4.01.19 Two sets of lifting lugs (one for transformer with oil and other for tank cover).

4.01.20 Jacking pads.

4.01.21 Skids and pulling eyes on both sides.

4.01.22 Air release devices.

4.01.23 Inspection cover.

4.01.24 Oil filling hole and cap.

4.01.25 Tank mounted marshalling box.

4.01.26 Detachable, flat, bidirectional rollers with 90 deg. swivel mechanism.

4.01.27 Clamping arrangement for rollers.

4.01.28 Ground support for cable box.

4.01.29 Neutral CT secondary box.

4.01.30 Haulage facilities.

`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 14 of 30 

 
4.01.31 Two nos. spring operated pressure relief devices with extension pipe to bring oil to
plinth level along with electrically insulated contact for alarm and tripping for
transformer rating 2 MVA and above.

4.01.32 Gas collection device along with all accessories.

4.02.00 Breather shall be fitted at a height not exceeding 1.5 M.

4.03.00 Rating and diagram plate shall be fitted at a height of about 1.75 M above the
ground level.

4.04.00 The WTI and OTI shall have accuracy class of + 2 deg. C or better.

4.05.00 Rating/ Name/ Valve schedule plates shall be of white non-hygroscopic material with
engraved black lettering. Such plates shall be bi- lingual (requirement will be
finalised during detailed engineering) with Hindi inscription first, followed by
English. Alternatively, two separate plates with Hindi & English inscription shall be
provided.

5.00.00 PAINTING

Paint shade shall be informed to successful bidder during detail engineering as

applicable for specific project. Adequate quantity of touch up paint shall also be
supplied. There shall be no commercial or delivery implication to BHEL on account
of paint shade, paint specification/ procedure.

6.00.00 QUALITY ASSURANCE, TESTING & INSPECTION

6.01.00 BHEL’s Standard QP (PE-QP-999-302-E001 Rev. 0) is enclosed as per Annexure-

A of section-II, volume-II for reference. In case bidder has reference QP agreed with
ultimate customer, same can be submitted for specific project after award of contract
for BHEL/ ultimate customer’s approval. There shall be no commercial or delivery
implication to BHEL on account of QP approval.

6.02.00 All materials, components and accessories of the transformers shall be procured,
manufactured, inspected and tested by vendor/ sub-vendor as per approved quality
plan.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 15 of 30 

 
6.03.00 Tests shall be performed in presence of Purchaser’s representative. The bidder shall
give at least fifteen (15) days advance notice of date when the tests are to be carried
out.

6.04.00 All routine and acceptance tests as per relevant standards and specification shall be
carried out by the vendor/ sub-vendor on all transformers.

6.05.00 Successful bidder shall furnish List of sub-vendors/ makes of items for BHEL/
customer approval at contract stage. This shall not have any commercial implication
to BHEL.

6.06.00 For acceptance of short circuit reports for tests carried out earlier on similar
transformers, successful bidder shall furnish the following documents for BHEL/
BHEL’s customer acceptance without any commercial/ delivery implication to BHEL

6.06.01 Calculations and design considerations to prove ability to withstand the dynamic
effects of short circuit.

6.06.02 Short circuit test report of previously tested similar transformer for validation by
comparison. Criteria for similarity of transformer for acceptance of Short circuit test
report shall be as given in the Annexure-B of IEC-60076-5.

7.00.00 COMMISSIONING SPARES, SPECIAL TOOLS & TACKLES AND O & M

SPARES

7.01.00 Commissioning spares are those, which may be required during commissioning of
the equipment. Bidder to furnish list of commissioning spares along with technical
offer as per annexure-IV of section-I, volume-II.

7.02.00 The bidder shall supply with the equipment, one unused complete set of all special
tools & tackles required for the erection, assembly, disassembly and proper
maintenance of the equipment. A list of such tools & tackles (price deemed to be
included in the total bid price) shall be submitted by the bidder along with the offer as
per annexure-V of section-I, volume-II.

7.03.00 O & M spares are those which are required for satisfactory & trouble free operation of
equipment. List of O & M spares is enclosed as per Annexure-D of section-II, volume-
II. O & M spares shall be quoted (if applicable) as per BOQ-cum-price schedule as part
of NIT.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 16 of 30 

 
8.00.00 O & M MANUALS

8.01.00 O & M manuals for the installation, operation and maintenance of transformers
shall be furnished at least three months before despatch of equipment.
8.02.00 Draft manual should first be submitted for purchaser’s approval. The manual
should contain minimum following details:
8.02.01 General description of equipment.
8.02.02 Approved Technical Data Sheet
8.02.03 All drawings
8.02.04 Salient constructional features.
8.02.05 Technical leaflets of fittings/ important parts.
8.02.06 Type and routine test certificates.
8.02.07 Instructions to be followed on receipt of equipment at site & for storage.
8.02.08 Instructions for foundation arrangement.
8.02.09 Erection procedures and checks.
8.02.10 Pre-commissioning checks.
8.02.11 Commissioning procedures.
8.02.12 Withdrawal arrangement/ material handling instructions.
8.02.13 Operation instructions.
8.02.14 Maintenance instructions.
8.02.15 Trouble-shooting.
8.02.16 Safety instructions.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 17 of 30 

ANNEXURE - A

STANDARD QUALITY PLAN

 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

QUALITY PLAN BIDDER/ : STANDARD QP NO. : PE-QP-999-302-E001, REV. 0 SPECIFICATION TITLE:

VENDOR

SHEET 1 OF 10 SYSTEM ITEM :OIL FILLED TRANSFORMER DOC. NO. :

SL. COMPONENT/OPERATIONCHARACTERISTIC CAT. TYPE/ EXTENT OF REFERENCE ACCEPTANCE FORMAT AGENCY REMARKS
NO. CHECK METHOD OF CHECK DOCUMENT NORM OF RECORD
CHECK P W V

1 2 3 4 5 6 7 8 9 10 11

1.0 RAW MATERIALS & BOUGHT OUT ITEMS

1.1 Mild Steel plate,

a) Thickness Major MEASURE 10% QC Record. 3/2 1
MS Pipe, Channels, b) Surface defects Major VISUAL 100% QC Record. 3/2 2
MS Angles c) Chemical composition Major TEST - Supplier's TC 3/2 -
d) Mechanical Properties Major TEST - 'MANFUF. STD / 'MANFUF. STD / Supplier's TC 3/2 2
e) Hydraulic test of pipes Major TEST - IS:2062 / IS:1239 IS:2062 / IS:1239 Supplier's TC 3/2 2
1.2 CRGO Steel a) Thickness Dimension & Finish Major MEASURE 10% DRG/DATA SHEET/ DRG/DATA SHEET/ QC Record. 2 1
b) Grade of CRGO Major MEASURE - 'MANFUF. STD / 'MANFUF. STD / TC 3/2 2
c) Cutting & burr Major MEASURE 10% IS:3024 / IS:649 IS:3024 / IS:649 QC Record. 2 -
d) Scratches, surface finish Major VISUAL 10% QC Record. 3/2 -
e) Waviness & edge camber Major MEASURE 10% QC Record. 2 1
f) Specific core loss Major TEST - Supplier's TC 3/2 2
g) Surface resistivity Major TEST - Supplier's TC 3/2 2
h) Stacking factor Major TEST - Supplier's TC 3/2 2
i) Permeability Major TEST - Supplier's TC 3/2 2
j) Bend test/ Ductility Major MEASURE - Supplier's TC 3/2 2
1.3 Paper Insulated a) Dimensions Major MEASURE 100% 'MANFUF. STD / 'MANFUF. STD / QC Record. 2 1
Copper Conductor b) Resistivity/Conductivity Major TEST 10% IS:13730-P-27/IEC IS:13730-P-27/IEC Supplier's TC 3/2 1
c) Elongation Major TEST - 60554 60554 Supplier's TC 3/2 2
d) Tensile Strength Major TEST - Supplier's TC 3/2 2
e) Proof stress if applicable Major TEST - Supplier's TC 3/2 2
f) Insulation test between strands Major TEST - Supplier's TC 3/2 2
for bunched conductors
g) Cu purity of CC rod Major TEST - Supplier's TC 3/2 2
h) Chemical composition Major TEST - Supplier's TC 3/2 2
Free from sharp Free from sharp
i) Surface Finish Major VISUAL 100% edge,burr,scretch, edge,burr,scretch, QC Record. 2 2
cuts etc. cuts etc.
1.4 Insulating Paper a) Dimensions Major MEASURE 10% 'MANFUF. STD / 'MANFUF. STD / QC Record. 2 1
b) Density & substance Major TEST - IS:9335-P-2/IS:9335- IS:9335-P-2/IS:9335- Supplier's TC 3/2 2
c) Tensile Strength Major TEST - P-III/IEC 60554 P-III/IEC 60554 Supplier's TC 3/2 2
d) Elongation Major TEST - Supplier's TC 3/2 2
e) Water absorption Major TEST - Supplier's TC 3/2 2
f) Moisture content Major TEST - Supplier's TC 3/2 2
g) pH value & conductivity Major TEST - Supplier's TC 3/2 2
aqueous extract
h) Ash content Major TEST - Supplier's TC 3/2 2
i) Electrical strength Major TEST - Supplier's TC 3/2 2
j) Air permeability Major TEST - Supplier's TC 3/2 2
k)Tear index Major TEST - Supplier's TC 3/2 2
I) Heat stability Major TEST - Supplier's TC 3/2 2

BHEL PARTICULARS BIDDER/VENDOR

NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

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VENDOR

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CHECK P W V

1 2 3 4 5 6 7 8 9 10 11

1.5 Insulation & Press- a) Dimension Major Measure 10% 'MANFUF. STD / 'MANFUF. STD / QC Record. 2 1
IS:1576 IS:1576
Board moulding b) Compressibility
Major Test - Supplier's TC 3/2 2
( stock items) c) Density
Major Test - Supplier's TC 3/2 2
d) Tensile strength Major Test - Supplier's TC 3/2 2
e) pH value/Conductivity
of water extract Major Test - Supplier's TC 3/2 2
f) Electrical strength in air & oil Major Test - Supplier's TC 3/2 2
g) Shrinkage in air Major Test - Supplier's TC 3/2 2
h) Flexibility Major Test - Supplier's TC 3/2 2
i) Ash content Major Test - Supplier's TC 3/2 2
j) Moisture content Major Test - Supplier's TC 3/2 2
k) Cohesion between plies Major Test - Supplier's TC 3/2 2
I) Elongation Major Test - Supplier's TC 3/2 2
m) Oil absorption Major Test - Supplier's TC 3/2 2
1.6 Densified wood a) Dimension Major Measure 10% 'MANFUF. STD / 'MANFUF. STD / QC Record. 2 1
b) Surface finish Major Visual 10% IS:3513 IS:3513 QC Record. 2 -
c) Electrical strength in oil Major Test - Supplier's TC 3/2 1
d) Oil absorption Major Test - Supplier's TC 3/2 -
e) Moisture content Major Test - Supplier's TC 3/2 -
f) Compression strength Major Test - Supplier's TC 3/2 -
g) Crossbreaking strength Major Test - Supplier's TC 3/2 -
h) Tensile strength Major Test - Supplier's TC 3/2 -
i) Specific gravity/ Density Major Test - Supplier's TC 3/2 -
1.7 Gasket(Rubber a) Dimension Major Measure 10% 'MANFUF. STD / 'MANFUF. STD / QC Record. 2 -
Bonded Cork sheet b) Hardness Major Test - IS:4253 IS:4253 Supplier's TC 3/2 1
(if applicable) c) Tensile strength Major Test - Supplier's TC 3/2 -
d) Compressibility Major Test - Supplier's TC 3/2 1
e) Recovery Major Test - Supplier's TC 3/2 -
f) Compression set Major Test - Supplier's TC 3/2 -
g) Flexibility Major Test - Supplier's TC 3/2 -
h) Fluid resistence test Major Test - Supplier's TC 3/2 -
i) Chloride/Sulphate content of water
Major Test - Supplier's TC 3/2
extract -
j) Density Major Test - Supplier's TC 3/2 -
1.8 Nitrile Rubber a) Dimension Major MEASURE 10% 'MANFUF. STD / 'MANFUF. STD / Supplier's TC 2 -
Cord and "0" b) Shore Hardness Major Test - IS:4253 IS:4253 Supplier's TC 3/2 -
Ring c) Tensile strength Major Test - Supplier's TC 3/2 -
(if applicable) d) Elongation at break Major Test - Supplier's TC 3/2 -
e) Compression set Major Test - Supplier's TC 3/2 -
f) Accelerated Ageing in oil Major Test - Supplier's TC 3/2 -

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

QUALITY PLAN BIDDER/ : STANDARD QP NO. : PE-QP-999-302-E001, REV. 0 SPECIFICATION TITLE:

VENDOR

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NO. CHECK METHOD OF CHECK DOCUMENT NORM OF RECORD
CHECK P W V

1 2 3 4 5 6 7 8 9 10 11

1.9 Insulating Oil a) Appearance of oil Major Visual Supplier's TC 3/2 2,1
b) Density at 29.5 deg C Major Test Supplier's TC 2,1
c) Kinematic viscosity at 27 Major Test Supplier's TC 2,1
& 40 deg C Supplier's TC
d) Interfacial tension at 27 deg C Major Test Supplier's TC 2,1
e) Flash point Major Test Supplier's TC 2,1
f) Pour point Major Test Supplier's TC 2,1
g) Neutralization value Major Test Supplier's TC 2,1
h) Corrosive sulphur Major Test Supplier's TC 2,1
i) Dielectric dissipation factor Major Test Supplier's TC 2,1
j) Specific resistance Major Test MANFUF. STD / MANFUF. STD / Supplier's TC 2,1
(resistivity) One sample IS:335 IS:335
k) Ageing characteristics Major Test Supplier's TC 2,1
after accelerated ageing
I) Oxidation stability Major Test Supplier's TC 2,1
m) Presence of oxidation Major Test Supplier's TC 2,1
inhibitor
n) Electric strength(BDV, Tan-delta) Major Test Supplier's TC 2,1
i) As delivered
ii) After treatment
o) Water content Major Test Supplier's TC 2,1
p) S.K.value Major Test Supplier's TC 2,1

1.10 Paint &Varnish Shelf Life Major VISUAL 100% MANF.STD MANF.STD Supplier's TC 3/2 2,1

2 FITTING AND ACCESSORIES (MAKE SHALL BE AS PER ANNEXURE-1)

2.1 Porcelain a) Dimension Major MEASURE 100% IS:2099/IS:8603 IS:2099/IS:8603 QC records 2 -

Bushing
b) Visual defects Major Visual 100% QC records 2 -
( if applicable)
c) routine testing Major Test 100% Supplier's TC 3/2 2,1
2.2 Condenser a) Type, size & model Major Visual 100% IS:2099 / IS:8603 / IS:2099 / IS:8603 / QC records 2 1
Bushing b) Dimensional check Major Measure 100% IEC 60137 IEC 60137 QC records 2 1
(if applicable) c) Dry power frequency Major Test - Supplier's TC 3/2 2,1
voltage withstand test Major Test -
d) HV Test for test tap Major Test - Supplier's TC 3/2 2,1
e) Tan delta & capacitance test Major Test - Supplier's TC 3/2 2,1
f) Nitrogen Pressure Test Major Test - Supplier's TC 3/2 2,1
g) Routine Test Major Test - Supplier's TC 3/2 2,1

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

QUALITY PLAN BIDDER/ : STANDARD QP NO. : PE-QP-999-302-E001, REV. 0 SPECIFICATION TITLE:

VENDOR

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NO. CHECK METHOD OF CHECK DOCUMENT NORM OF RECORD
CHECK P W V

1 2 3 4 5 6 7 8 9 10 11

2.3 Bucholz Relay a) Type, size & make Major Visual 100% MANFUF. STD./' MANFUF. STD./' QC records 2 1
b) Continuity for alarm & Major Test - IS:3637 IS:3637 Supplier's TC 3/2 2
trip (Performance) Major Test -
c) Porosity test Major Test - Supplier's TC 3/2 2
d) High voltage & IR test Major Test - Supplier's TC 3/2 2
e) Element test Major Test - Supplier's TC 3/2 2
f) Gas volume test Major Test - Supplier's TC 3/2 2,1
g) Loss of oil & surge test Major Test - Supplier's TC 3/2 2,1
2.4 Pressure a) Type, size & make Major Visual 100% MANFUF. STD./' MANFUF. STD./' QC records 2 1
Relief Device b) Operation (Pressure & Major Test - IS:3637 IS:3637 Supplier's TC 3/2 2,1
flag indication) Major Test -
c) HV Test Major Test - Supplier's TC 3/2 2,1
d) Switch contact operation Major Test - Supplier's TC 3/2 2
2.5 Magnetic Oil a) Type, size & make Major Visual 100% MANFUF. STD' MANFUF. STD.' QC records 2 1
Lavel Gauge b) Dial marking Major Visual - Supplier's TC 3/2 2
(MOG) c) Switch continuity Major Test - Supplier's TC 3/2 2
d) HV test Major Test - Supplier's TC 3/2 2
e) Operation test Major Test - Supplier's TC 3/2 2
2.6 Off-Circuit Tap a) Dimensions Major Measure 100% MANFUF. STD' MANFUF. STD' QC records 2 -
Changer/Switch b) Physical condition Major Visual 100% QC records 2 -
(if applicable) c) operation of switch 2
Major Test - QC records -
d) Insulation resistance test Major Test - Supplier's TC 3/2 2
e) Leak test of handle stuffing box Major Test - Supplier's TC 3/2 2
f) Milli volt drop test Major Test - Supplier's TC 3/2 2
2.7 On load Tap a) Visual check Major Visual 100% IS:8468/IEC 60214 IS:8468/IEC 60214 QC records 2 -
Changer b) Dimensional check Major Measure 100% Supplier's TC 2 -
(if applicable) c) Mechanical operation on 3/2
Major Verify - Supplier's TC 2
Diverter & Selector switch,
4000 switching oper. (Min)
d) HV test on Auxiliary circuit Major Test - Supplier's TC 3/2 2,1
e) Sequence test Major Test - Supplier's TC 3/2 2,1
f) Pressuure test of diverter Major Test - Supplier's TC 3/2 2,1
switch compartment with oil
g) Mechanical test of Tap Major Test - Supplier's TC 3/2 2,1
selector with motor drive
500 satisfactory opm(in all)
from one extreme position
to the other in air
h) Opm test of complete Major Test - Supplier's TC 3/2 2,1
tapchanger
i) Aux. ckt. HV test at 2 KV for 1 min. Major Test - Supplier's TC 3/2 2,1

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

QUALITY PLAN BIDDER/ : STANDARD QP NO. : PE-QP-999-302-E001, REV. 0 SPECIFICATION TITLE:

VENDOR

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CHECK P W V

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2.8 Gun Metal / Cast a) Dimensional check Major Measure 100% Manf. Std./IS:778 Manf. Std./IS:778 QC Record 2 -
Iron Valves b) Type, size & make 100% Class 1 Class 1
Gate/globe/ Major Visual QC Record 2 -
Butterfly) c) Leakage test(Hydraulic test Major Test - Supplier's TC 3/2 2,1
for Body & Seat) Major Test -
d) Operational test (close & open) Major Test - Supplier's TC 3/2 2
2.9 Bushing CT a) Visual check/Dimensional Major Measure/Visual test 100% Manf. Std./IS:2705 Manf. Std./IS:2705 Supplier's TC
check 2
-
Major Test - Manf. Std./IS:2705 Manf. Std./IS:2705 Supplier's TC
3/2 2,1
b) Routin test
2.10 Marshaling box/RTCC a) Visual check for wiring Major Test 100% Drg./Manf. Drg./Manf. Supplier's TC 3/2 2 -
b) Dimensional check Major Measure/Test 100% Std./IS:5/IS:13947 Std./IS:5/IS:13947 Supplier's TC 3/2 2 -
c) Check for make of Major Measure/Test 100% Supplier's TC 3/2 2 -
components
d) 2 kV insulation test on Major Measure/Test 100% Supplier's TC 3/2 2 -
auxiliary wiring
e) Check for paint, shade & Major Measure/Test 100% Supplier's TC 3/2 2 -
thickness
f) Degree of Prot. By paper insertion Major Measure/Test 100% Supplier's TC 3/2 2 -
2.11 OTI&WTI a)Type size & make Major Visual 100% Manf. Std. Manf. Std. QC records 2 1
b) HV test Major Test - Supplier's TC 3/2 2,1
C) Temperature calibration Major Test - Supplier's TC 3/2 2,1
d) Switch setting & switch deferential Major Test - Supplier's TC 3/2 2,1
e) Calibration & operation of switch Major Test - Supplier's TC 3/2 2,1
2.12 Radiator a) Type, Model, Rating Major Visual 100% Drg./Manf. Drg./Manf. QC records 3/2 2 1
b) Dimensions & No. of elements Major Measure 100% Std./IS:101 Std./IS:101 QC records 3/2 2 -
c) Paint shade, Finish & Major Measure/test 100% QC records 3/2 2 -
film thickness
d) Pressure test Major Test 100% Supplier's TC 3/2 2 1
e) Adhesion test on paint Major Test 100%
f) Welding quality Major Visual/ DPTest 100% Relevant code Relevant code Supplier's TC 3/2 2 1
2.13 Hardware a) Dimensional check Major Measure 100% Manf. Std. Manf. Std. QC records 2 -
b) Tensile strength Major Test - Supplier's TC 3/2 -

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

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VENDOR

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CHECK P W V

1 2 3 4 5 6 7 8 9 10 11

2.14 Oil Pump Motor a) Type, Model, Rating Major Visual 100% Manf. Std. Manf. Std. QC records 2 -
set b) Dimensional check Major Measure 100% QC records 2 -
(if applicable) Supplier's TC
c) Hv test at 2 kV for one minute Major Test - 3/2 2,1
d) Input power taken by pump Major Test - Supplier's TC 3/2 2,1
e) Performance test ( Major Test - Supplier's TC 3/2 2,1
I/P,O/P,DISCH, NO LOAD,
Locked Rotor te )
2.15 Cooling Fan a) Type, Model, Rating Major Visual 100% Approved Approved QC records 2 -
(if applicable) b) Dimensional check Major Measure - drgs/docs/spec./ drgs/docs/spec./ QC records 2 -
IS:2312 IS:2312 Supplier's TC
c) HV test at 2 KV for Major Test - 3/2 2,1
one minute Major Test - -
d) IR test Major Test - Supplier's TC 3/2 -
e) Power consumption & RPM Major Test - Supplier's TC 3/2 2,1
2.16 Roller Assembly a)Dimensions Major Measure 100% Manf. Drg./docs Manf. Drg./docs QC records 2 -
b) Mechanical & Chemical Major Measure - Supplier's TC 3/2 2
properties of Raw material
used for Shaft & Roller
2.17 Terminal a) Dimensional check Major Measure 100% Manf. Manf. QC records 2 -
Connector b) Surface finish Major Visual - Drg./docs/IS:5561 Drg./docs/IS:5561 Supplier's TC 3/2 2
(if applicable) c) Acceptance test Major Test - Supplier's TC 3/2 2,1
2.18 Air Cell for a) Dimensional check Major Measure 100% Manf. Drg./docs/PO Manf. Drg./docs/PO QC records 2 -
Conservator b) Surface finish Major Visual 100% Supplier's TC 3/2 2
(if applicable) c) Acceptance test Major Test 100% Supplier's TC 3/2 2,1
2.19 Oil Flow a) Type, Model, Rating Major Visual 100% Manf. Manf. QC records 2 -
Indicator b) Dimensional check Major Measure 100% Drg./docs/Spec. Drg./docs/Spec. QC records 2 -
(if applicable) c) Functional test Major Test - Supplier's TC 3/2 2,1
2.20 Silicagel a) Type, Size, Model Major Visual 100% Manf. Manf. QC records 2 -
Breather b) Pressure/ Leakage test Major Test - Drg./docs/Spec. Drg./docs/Spec. Supplier's TC 3/2 2
c) Colour of silica gel Major Visual - Supplier's TC 3/2 2,1

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

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VENDOR

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1 2 3 4 5 6 7 8 9 10 11

3 IN-PROCESS
3.1 Fabrication of Tank, a) Welding procedure specification Major Verify/Review 100% QC Records 3/2 2
Conservator,Radiator, b) Process qualification record Major Verify/Review 100% QC Records 3/2 2
HV&LV CABLE BOX and
c) Weider qualification Major Verify/Review 100% QC Records 3/2 2
welding requirement
d) Welding electrodes-Me- Major Verify/Review 100% QC Records 3/2 2
chanical Properties
e) Fitup for butt weld joints Major Visual 100% QC Records 3/2 2
of tank and cover
f) Visual check on weldment & Major Visual 100% QC Records 3/2 2
any foregin particle in the
entire tank with conservator,
pipes etc.and blanking of
ends with bolted plates
Manf. Drg./stand. Manf. Drg./stand.
g) Dimensional check after Major Measure 100% QC Records 3/2 2
final welding incl.foundation
dimension-HV & LV cable
box/ Radiator/ Cooler/ Pipes
h) DP test on welded joints Major Test 100% QC Records 3/2 2,1
i) Check for flatness gasket surface Major Visual 100% QC Records 3/2 2,1
J) Rim flatness Major Measure 100% QC Records 3/2 2,1
k) Surface cleaning by sand/ Major Visual 100% QC Records 3/2 2,1
shot blasting
l) Primer coating, paint Major Measure 100% QC Records 3/2 2,1
shade thickness inside & outside
m) Paint film adhesion test Major Test 100% QC Records 3/2 2,1
n) Vacuum Test (Tank) CR Vacuum test 1 unit each type Appd. Doc./BHEL Appd. Doc./BHEL QC formate 3/2 1
o) Pressure test (Tank) CR Pressure test 1 unit each type SPEC./CBIP SPEC./CBIP QC formate 3/2 1
3.2 Core Stamping a) Burr & Bow Major Visual 100% QC Records 2 -
Manf. Drg./stand. Manf. Drg./stand.
b) Dimensional check Major Measure 100% QC Records 2 -
3.3 Core Building a) Dimensional check Major Measure 100% QC Records 2 -
b) Assembly of limb insulation Major Visual 100% QC Records 2 -
and limb plates.
c) Rectangularity of core assembly Major Visual 100% QC Records 2 -
d) Freedom from overlaps Major Visual 100% QC Records 2 -
& air gap at joints Manf. Drg./stand. Manf. Drg./stand.
e) Leaning of cor(i.e core verticality) Major Visual 100% QC Records 2 -
f) Limb & stack thickness Major Visual 100% QC Records 2 -
g) Limb clamping & binding Major Visual 100% QC Records 2 -
h) Core diameter Major Visual 100% QC Records 2 1
i) Earthing of core Major Visual 100% QC Records 2 1

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

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VENDOR

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3.4 Test on Core a) Dimensional check Major Measure 100% QC Records 2 -

b) Flux density measurement Major Measure 100% QC Records 2 -
c) Isolation test between(core to core Major Test 100% QC Records 2 -
clamps)
d)Torque Tightness Major Measure 100% QC Records 2 -
Manf. Drg./stand. Manf. Drg./stand.
e) Core Insulation Major Electrical 100% QC Records 2 -
f) Core Loss Major Electrical with dummy 100% QC Records 2 1
coil
g)Visual checks of core verticality Major Visual 100% QC Records 2 -

3.5 Winding a) Brazing procedure & Major Review 100% QC Records 2 -

Brazer qualification
b) Conductor size. Major Measure 100% QC Records 2 -
c) Redial depth of winding Major Measure 100% QC Records 2 -
d) Anchoring & binding at Major Measure 100% QC Records 2 -
start & finish
e) No. of turns Major Measure 100% QC Records 2 -
f) Transposition of cross-overs Major Measure 100% QC Records 2 -
Manf. Drg./Relevant Manf. Drg./Relevant
g) Dimensional check Major Measure 100% stand. QC Records 2 -
stand.
(0D,ID & axial length)
h) Insulation arrangement & alignmt. Major Measure 100% QC Records 2 -
i) Winding length Major Measure 100% QC Records 2 -
j) Brazed joints Major Measure 100% QC Records 2 -
k) Lead & coil identification and Major Measure 100% QC Records 2 -
marking
I) Free from damages Major Measure 100% QC Records 2 -
m) Continuity test for leads Major Measure 100% QC Records 2 -
n) Turn to Turn Insulation Major Measure 100% QC Records 2 1
o) Measure. Of Resistance Major Measure 100% QC Records 2 1
3.6 Core coil assembly a) Cleanliness of core Major Visual 100% QC Records 2 -
b) Alignment of spacers/blocks Major Visual 100% QC Records 2 -
c) Elect. Clearance & Insp. Major Visual/measure 100% QC Records 2 -
Manf. Drg./Relevant Manf. Drg./Relevant
Of core & coil assly after
stand. stand.
completion of terminal gear
d) Check provision of core Major Visual 100% QC Records 2 -
frame earthing
3.7 Connection and Tap a) Ratio test on all taps Major Test 100% QC Records 2 1
switch assembly b) Lead disposition. Major Visual 100% QC Records 2 -
c) Brazing of joints Major Visual 100% Manf. Drg./Relevant Manf. Drg./Relevant QC Records 2 -
d) Crimping of joints Major Visual 100% stand. stand. QC Records 2 -
e) Insulation over joints Major Visual 100% QC Records 2 -
f) Vector group Major Test 100% QC Records 2 1
3.8 Ovening and Tanking a) Cleanliness of tank Major Visual 100% QC Records 2 -
b) Drawing Major Physical 100% QC Records 2 1
c) Check tightness of clamped Major Measure 100% QC Records 2 1
blocks and measurements Manf. Drg./Relevant Manf. Drg./Relevant
of winding height stand. stand.
d) Electrical clearances Major Measure 100% QC Records 2 1
e) Oil filling and air release Major Physical 100% QC Records 2 -
f) Dryness (Tan-delta & I.R) Major Measure 100% QC Records 2 -

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

QUALITY PLAN BIDDER/ : STANDARD QP NO. : PE-QP-999-302-E001, REV. 0 SPECIFICATION TITLE:

VENDOR

SHEET 9 OF 10 SYSTEM ITEM :OIL FILLED TRANSFORMER DOC. NO. :

SL. COMPONENT/OPERATIONCHARACTERISTIC CAT. TYPE/ EXTENT OF REFERENCE ACCEPTANCE FORMAT AGENCY REMARKS
NO. CHECK METHOD OF CHECK DOCUMENT NORM OF RECORD
CHECK P W V

1 2 3 4 5 6 7 8 9 10 11

4 Type & Special a)Review of type test & special

Test on test report Type test as per
Transformer b) Review of all previous stage Major Verify 100% Reports 2 1 - enclosed annexure-1
of insp. As per QR prior to to be conducted.
final testing
5 ROUTINE TEST
Each Transformer Shall be
completely assembled with
all fittings and a) Verification of completeness
Major Measure 100% 2 1
accessoriesmeant for / Dimensional check
particular transformerbefore
offering for inspection &
Test
b) Measurement of Voltage Ratio at
all taps,polarity & Major Measure 100%
vector group verification 2 1
c) Measurement of winding resistance
on HV & LV on Major Measure 100%
all the Taps. 2 1
d) Vector group and polarity
Major Measure 100%
check 2 1
e) Magnetic balance Test Major Measure 100% 2 1

f) Induced overvoltage Major Measure 100%

2
g) Sepatate Source Voltage
Major Measure 100%
Withstand test 2 1

h)Measurementof capacitance & Tan As per APPROVED As per APPROVED Manf. Test
delta to determine DATA DATA Records/QC
Major Measure 100% SHEET/IS:2026 SHEET/IS:2026 Formats 2 1
capacitance between winding
& earth,

i) Measurement of No-load
losses & current at 90)%,
Major Measure 100%
100% & 110% rated voltage.
2 1
j) .2 kV core Isolation (If Major Measure 100% 2 1
Applicable),
k) Measurement of no load
Major Measure 100%
current with 415 V, 50 hZ AC supply. 2 1
l) IR & measurement of Insulation
power factor & capacitance between Major Measure 100%
winding and earth 2 1
m) Load loss & short circuit
Impedence measurement on principal Major Measure 100%
& extreme taps.
2 1
n) Repeat no load currents/loss
measurement after completion of all Major Measure 100%
dielectric test. 2 1
o) Test on OLTC/OCTC. Major Measure 100% 2 1

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
 CUSTOMER : PROJECT TITLE : SPECIFICATION NO. :

QUALITY PLAN BIDDER/ : STANDARD QP NO. : PE-QP-999-302-E001, REV. 0 SPECIFICATION TITLE:

VENDOR

SHEET 10 OF 10 SYSTEM ITEM :OIL FILLED TRANSFORMER DOC. NO. :

SL. COMPONENT/OPERATIONCHARACTERISTIC CAT. TYPE/ EXTENT OF REFERENCE ACCEPTANCE FORMAT AGENCY REMARKS
NO. CHECK METHOD OF CHECK DOCUMENT NORM OF RECORD
CHECK P W V

1 2 3 4 5 6 7 8 9 10 11

p) Verification of oil leakage test with all

fitting & accessories at normal presure Major Measure 100%
plus 35KPA for 24 hours. 2 1
q) Jacking Test followed by D.P. Test Major Measure 100%
2 1
r) Paint shade & adhession test Major Measure 100% 2 1
As per APPROVED As per APPROVED
s) Protection on M. Box by Manf. Test
Major Measure 100% DATA DATA
paper insertion Records/QC 2 1
SHEET/IS:2026/MAN SHEET/IS:2026/MAN
t) 2 KV test on M.Box wiring & Formats
F. STD. F. STD.
functional check for Major Measure 100%
component of MB 2 1
u) Slope and alignment of Buchhoz
Major visual 100%
relay 2 1

v) DFT of paint Major Measure 100%

2 1

Pre Shipment a) Transformer- verification of final

check &Despatch transportion.
6 2
b) Dew points measurement of
N2/Dry gas tightness/ Pr reading
2
(Only applicable for transformers
dispatched with Gas Filling)
c) Packing of loose items
2

PARTICULARS BIDDER/VENDOR
BHEL NAME
SIGNATURE
DATE BIDDER'S/VENDORS COMPANY SEAL
LEGEND : 1 - BHEL/ CUSTOMER 2 - VENDOR 3 - SUB- VENDOR P - PERFORM W - WITNESS V - VERIFICATION
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 28 of 30 

 
ANNEXURE - B
TRANSFORMER LOSSES

1. The No-Load and Load losses for transformers 2.0MVA & above and voltage ratio
33kV/6.9kV, 33kV/3.5kV, 11kV/6.9kV, 11kV/3.5kV, 6.6kV/3.5kV are given below:

Ratings Maximum No-Load losses Maximum Load losses at

at rated frequency and normal ratio, rated current
100%voltage and 75 deg. C
10.0 MVA 9.0kW 72.0kW
8.0MVA 7.5 kW 57.0kW
7.5 MVA 7.2 kW 50.0kW
6.3MVA 6.5kW 45.0kW
5.0MVA 5.5kW 36.0kW
3.5MVA 4.5kW 32.0kW
2.5 MVA 2.8kW 30.0kW
2.0MVA 2.4 kW 24.0kW

The above indicated maximum No-Load and Load losses are inclusive of permissible
tolerance as per IS-2026. Further tolerance on maximum losses is not permissible.

2. Transformers of rating 2.5MVA & below and voltage ratio 33kV/433V, 11kV/433V,
6.6kV/433V, 3.3kV/433V shall have Energy Efficiency Level 1 as per IS-1180.
However, percent impedance shall be as per Data Sheet-A of section-I, volume-II of
technical specification.
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 29 of 30 

 
ANNEXURE – C
`   
 TITLE  :  SPECIFICATION NO.
PE-SS-999-302-E001
STANDARD TECHNICAL SPECIFICATION FOR 

OIL FILLED SERVICE TRANSFORMERS  VOLUME NO.  :       II 

SECTION          :   II 
  REV NO. : 00 DATE : 30/06/2016

SHEET : 30 of 30 

 
ANNEXURE – D

LIST OF O & M SPARES

S. NO. DESCRIPTION QTY

1 HV bushing with metal parts & gaskets 1 no. for each rating

2 LV bushing with metal parts & gaskets 1 no. for each rating

3 WTI with alarm & trip contacts 1 no.

4 OTI with alarm & trip contacts 1 no.

5 Magnetic oil level gauge 1 no.

6 Diaphragm of explosion vent 1 no.

7 Buchholz relay 1 no.

8 Silica gel charge Three charge

9 Floats with contacts for Buchholz relay 1 set

10 Set of gaskets 2 sets

11 Set of valves (1 no. of each size & Type) 1 set

12 Set of windings for one limb in a suitable oil container 1 no. of each rating & type
(container shall be completely filled with transformer of transformer.
oil)
13 Contact for tap changer 1 set

14 Pressure relief device for 2MVA & above transformers 1 no.

15 Hydraulic/screw Jacks 4 no.

16 Any other item considered essential by the bidder
Note:
1) Wherever set is indicated above, it means the total parts/ accessories required to replace the particular item
for a given equipment

2) O & M spares shall be supplied along with transformers and packed separately with proper inscription.