SkipperSeil Ltd.

Guaranteed & Technical Particulars of Transformers

Sl. No. Description Units Data
A GSUT (to be furnished separately for GTG & STG)
1 Name & Place of Manufacturer Skipperseil Limited, India
2 Service Outdoor
3 Application/Designation - -
4 Reference Standards - IEC 60076
5 MVA rating (ONAF / ONAN cooling) MVA 70/56
6 Rated no load voltage ratio 225/11
7 Rated frequency Hz 50
8 Number of phases - 3
9 Winding Connections (HV & LV) - HV : STAR, LV: DELTA
10 Vector group YNd1
11 Type of Tap Changer - High Speed transistion Resistor
a) Range - +10% to -10% in the steps of 2.5%
b) Number of steps 16
c) Voltage variation effected on (HV/LV) - HV
d) Type of Voltage variation - CFVV
12 Reference ambient temperatures
a) Maximum ambient air temperature Deg C 40
b) Maximum daily monthly average ambient air temperature Deg C 40
c) Maximum yearly weighted average ambient temperature Deg C 20
13 Type of Transformer Neutral earthing for HV
14 Type of Cooling ONAF/ONAN
15 Temperature rise over 40 deg C ambient
a) Top oil by Thermometer method Deg C 60
b) Windings by Resistance method Deg C 65
16 Hot spot temperature Deg C 78
17 Efficiencies at 75 Deg. C at Unity Power factor
a) at full load % 99.51
b) at 3/4 of full load % 99.59
c) at 1/2 of full load % 99.66
18 Regulation at full load at 75 deg. C
a) at unity power factor % 1.21
b) at 0.85 p.f. lagging % 7.49
Total losses at rated voltage at Principal tapping & at rated frequency
19 kW 351.5 (±IEC Tol)
including auxiliary loss
20 Component losses
a) No load loss at rated voltage on principal tapping & at rated
kW 45 (±IEC Tol)
frequency
b) Load loss at rated current at principal tapping at 75 Deg. C
kW 300 (±IEC Tol)
excluding auxiliary loss
c) Auxiliary losses (Cooler loss) kW 6.5 (Max)
Impedance voltage at rated current at nominal tap / minimum tap / 12.5 (±IEC Tol.) @ Rated Tap & 70
21 %
maximum tap MVA
22 Reactance at rated current & rated frequency ( HV-LV ) % 12.49 (Approx.)
23 No load current at rated voltage and rated frequency % 1 (Approx.)
Separate source power frequency withstand voltage Insulation level of
24 kV rms HV : 460, HVN : 38 & LV: 28
HV & LV windings
25 Induced over Voltage withstand level of HV & LV windings kV rms As per IEC
26 Full wave lightning Impulse withstand voltage of HV & LV windings kVp HV : 1050, HVN : 95 & LV: 75
27 Switching Impulse withstand voltage of HV & LV windings kVp As per IEC
28 Short circuit withstand current & Duration
29 No. of radiators / radiator bank 2
30 Rating of each radiator bank % 50
31 Type of Termination for HV & LV
32 HV Terminal arrangement
a) Type Oil Impregnated Paper
b) Minimum Creepage distance mm 31
c) Lightening impulse voltage kVP 1050
d) Power frequency withstand voltage kVrms 460
33 LV Terminal arrangement
a) Type Oil communicating Porcelain
b) Minimum Creepage distance mm 31
c) Lightening impulse voltage kVP 75
d) Power frequency withstand voltage kVrms 28
34 HV Neutral Terminal arrangement
a) Type Oil communicating Porcelain
b) Minimum Creepage distance mm 31
c) Lightening impulse voltage kVP 95
d) Power frequency withstand voltage kVrms 38
35 Oil quantity required for first filling Ltrs. 22300
36 Max. flux density in core at tap which corresponds to
a) Rated voltage & frequency Tesla 1.72
b) 110% rated voltage & 100% rated frequency Tesla 1.892
c) 125% rated voltage & 100% rated frequency Tesla 2.15
d) 140% rated voltage & 100% rated frequency Tesla 2.408
37 Overfluxing withstand capability of transformer at
a) 110% rated voltage & 100% rated frequency sec. Continious
b) 125% rated voltage & 100% rated frequency sec. 60

File Name : DATA SHEET 70,56 & 12 MVA Sheet 1 of 6

 Sl. No. Description Units Data
c) 140% rated voltage & 100% rated frequency sec. 5
38 Resistance per phase at 75 deg C winding temperature of
a) HV windings( principal tap) ohm
Will be provided DDE
b) LV windings ohm
Amps/
39 Winding Current density for HV & LV ≤ 3.6 at Rated Tap
sq.mm
40 Vacuum withstand capability of tank
41 Thickness of transformer tank ( side / bottom / top plates ) mm 8/12/16
42 Core
a) Material of core laminations CRGO
b) Thickness of core laminations mm 0.27
c) Type and thickness of insulation of core laminations Pressboard
43 Means adopted to prevent displacement of core in tank during
a) Transport from works to site
b) Short circuits Will be provided DDE
c) Seismic disturbances
44 Type of Oil preservation system
a) Total volume of conservator Litres 10% of Total Tank Oil
b) Type of conservator .
45 Volume of conservator between highest and lowest levels Litres Will be provided DDE
46 CT particulars as applicable
HV : 250/1/1/1 A
a) Current ratio HVN : 250/1/1 A
LV : 4000/1/1 A
HV : PX/PX/PX/PX, Vk≤ 50V, Im≤150
mA @Vk/2, Rct<2Ω
HVN : PX/5P20, Vk≤ 50V, Im≤150 mA
b) Burden and accuracy class
@Vk/2, Rct<2Ω, 10 VA
LV : PX/PX, Vk≤ 200V, Im≤30 mA
@Vk/2, Rct<25Ω
c) Short time withstand current in amps and duration in sec Will be provided DDE
47 Cooling Fans for each radiator bank
a) Type Industrial
b) No. of working & standby fans 8 Working + 2 Standby
c) Motor rating kW 0.5
48 Cooling pumps for each radiator bank.
a) Type
b) Number of pumps NA
c) Motor rating kW
49 Tap Changer
a) Make E-MR/CTR/Equivalent
b) Type High Speed transistion Resistor
c) Voltage variation effected on (HV/LV) HV
d) Type of Voltage variation CFVV
e) Voltage rating 72.5 kV
f) Current rating 500 Amps
g) Step voltage Volts 2812.5
h) No of steps 16
i) OLTC Motor
□ kW rating
□ Voltage rating
□ Class of insulation Will be provided DDE
□ Degree of protection
□ Duty
50 RTCC Panel
a) Make Skipper Approved Vendor
b) Panel material and thickness 2 mm CRCA Sheet
c) Degree of Protection IP 43
NOTE:- (1) All the weights & dimension are liable to change without affecting performance parameter.
(2) All the efficiencies & regulations are calculated at guaranteed No Load Loss, Load Loss & % Impedance at 75°C.
(3) Cables, Glands and Lugs are not in scope of Skipperseil Limited.

0 Base Submittal 29.05.23

Rev. Description Date Prepared By

File Name : DATA SHEET 70,56 & 12 MVA Sheet 2 of 6

 SkipperSeil Ltd.
Guaranteed & Technical Particulars of Transformers
Sl. No. Description Units Data
A GSUT (to be furnished separately for GTG & STG)
1 Name & Place of Manufacturer Skipperseil Limited, India
2 Service Outdoor
3 Application/Designation - -
4 Reference Standards - IEC 60076
5 MVA rating (ONAF / ONAN cooling) MVA 56/45
6 Rated no load voltage ratio 225/11
7 Rated frequency Hz 50
8 Number of phases - 3
9 Winding Connections (HV & LV) - HV : STAR, LV: DELTA
10 Vector group YNd1
11 Type of Tap Changer - High Speed transistion Resistor
a) Range - +10% to -10% in the steps of 2.5%
b) Number of steps 16
c) Voltage variation effected on (HV/LV) - HV
d) Type of Voltage variation - CFVV
12 Reference ambient temperatures
a) Maximum ambient air temperature Deg C 40
b) Maximum daily monthly average ambient air temperature Deg C 40
c) Maximum yearly weighted average ambient temperature Deg C 20
13 Type of Transformer Neutral earthing for HV
14 Type of Cooling ONAF/ONAN
15 Temperature rise over 40 deg C ambient
a) Top oil by Thermometer method Deg C 60
b) Windings by Resistance method Deg C 65
16 Hot spot temperature Deg C 78
17 Efficiencies at 75 Deg. C at Unity Power factor
a) at full load % 99.49
b) at 3/4 of full load % 99.58
c) at 1/2 of full load % 99.65
18 Regulation at full load at 75 deg. C
a) at unity power factor % 1.23
b) at 0.85 p.f. lagging % 7.5
Total losses at rated voltage at Principal tapping & at rated frequency
19 kW 292.5 (±IEC Tol)
including auxiliary loss
20 Component losses
a) No load loss at rated voltage on principal tapping & at rated
kW 35 (±IEC Tol)
frequency
b) Load loss at rated current at principal tapping at 75 Deg. C excluding
kW 252 (±IEC Tol)
auxiliary loss
c) Auxiliary losses (Cooler loss) kW 5.5 (Max)
Impedance voltage at rated current at nominal tap / minimum tap /
21 % 12.5 (±IEC Tol.) @ Rated Tap & 56 MVA
maximum tap
22 Reactance at rated current & rated frequency ( HV-LV ) % 12.49 (Approx.)
23 No load current at rated voltage and rated frequency % 1 (Approx.)
Separate source power frequency withstand voltage Insulation level of
24 kV rms HV : 460, HVN : 38 & LV: 28
HV & LV windings
25 Induced over Voltage withstand level of HV & LV windings kV rms As per IEC
26 Full wave lightning Impulse withstand voltage of HV & LV windings kVp HV : 1050, HVN : 95 & LV: 75
27 Switching Impulse withstand voltage of HV & LV windings kVp As per IEC
28 Short circuit withstand current & Duration
29 No. of radiators / radiator bank 2
30 Rating of each radiator bank % 50
31 Type of Termination for HV & LV
32 HV Terminal arrangement
a) Type Oil Impregnated Paper
b) Minimum Creepage distance mm 31
c) Lightening impulse voltage kVP 1050
d) Power frequency withstand voltage kVrms 460
33 LV Terminal arrangement
a) Type Oil communicating Porcelain
b) Minimum Creepage distance mm 31
c) Lightening impulse voltage kVP 75
d) Power frequency withstand voltage kVrms 28
34 HV Neutral Terminal arrangement
a) Type Oil communicating Porcelain
b) Minimum Creepage distance mm 31
c) Lightening impulse voltage kVP 95
d) Power frequency withstand voltage kVrms 38
35 Oil quantity required for first filling Ltrs. 22300
36 Max. flux density in core at tap which corresponds to
a) Rated voltage & frequency Tesla 1.72
b) 110% rated voltage & 100% rated frequency Tesla 1.892
c) 125% rated voltage & 100% rated frequency Tesla 2.15
d) 140% rated voltage & 100% rated frequency Tesla 2.408
37 Overfluxing withstand capability of transformer at
a) 110% rated voltage & 100% rated frequency sec. Continious
b) 125% rated voltage & 100% rated frequency sec. 60
c) 140% rated voltage & 100% rated frequency sec. 5
38 Resistance per phase at 75 deg C winding temperature of
a) HV windings( principal tap) ohm
Will be provided DDE
b) LV windings ohm
Amps/
39 Winding Current density for HV & LV ≤ 3.6 at Rated Tap
sq.mm
40 Vacuum withstand capability of tank
41 Thickness of transformer tank ( side / bottom / top plates ) mm 8/12/16

File Name : DATA SHEET 70,56 & 12 MVA Sheet 3 of 6

 Sl. No. Description Units Data
42 Core
a) Material of core laminations CRGO
b) Thickness of core laminations mm 0.27
c) Type and thickness of insulation of core laminations Pressboard
43 Means adopted to prevent displacement of core in tank during
a) Transport from works to site
b) Short circuits Will be provided DDE
c) Seismic disturbances
44 Type of Oil preservation system
a) Total volume of conservator Litres 10% of Total Tank Oil
b) Type of conservator .
45 Volume of conservator between highest and lowest levels Litres Will be provided DDE
46 CT particulars as applicable
HV : 250/1/1/1 A
a) Current ratio HVN : 250/1/1 A
LV : 3200/1/1 A
HV : PX/PX/PX/PX, Vk≤ 50V, Im≤150
mA @Vk/2, Rct<2Ω
HVN : PX/5P20, Vk≤ 50V, Im≤150 mA
b) Burden and accuracy class
@Vk/2, Rct<2Ω, 10 VA
LV : PX/PX, Vk≤ 200V, Im≤30 mA
@Vk/2, Rct<20Ω
c) Short time withstand current in amps and duration in sec Will be provided DDE
47 Cooling Fans for each radiator bank
a) Type Industrial
b) No. of working & standby fans 8 Working + 2 Standby
c) Motor rating kW 0.5
48 Cooling pumps for each radiator bank.
a) Type
b) Number of pumps NA
c) Motor rating kW
49 Tap Changer
a) Make E-MR/CTR/Equivalent
b) Type High Speed transistion Resistor
c) Voltage variation effected on (HV/LV) HV
d) Type of Voltage variation CFVV
e) Voltage rating 72.5 kV
f) Current rating 500 Amps
g) Step voltage Volts 2812.5
h) No of steps 16
i) OLTC Motor
□ kW rating
□ Voltage rating
□ Class of insulation Will be provided DDE
□ Degree of protection
□ Duty
50 RTCC Panel
a) Make Skipper Approved Vendor
b) Panel material and thickness 2 mm CRCA Sheet
c) Degree of Protection IP 43
NOTE:- (1) All the weights & dimension are liable to change without affecting performance parameter.
(2) All the efficiencies & regulations are calculated at guaranteed No Load Loss, Load Loss & % Impedance at 75°C.
(3) Cables, Glands and Lugs are not in scope of Skipperseil Limited.

0 Base Submittal 29.05.23

Rev. Description Date Prepared By

File Name : DATA SHEET 70,56 & 12 MVA Sheet 4 of 6

 SkipperSeil Ltd.
Guaranteed & Technical Particulars of Transformers
Sl. No. Description Units Data
B Unit Auxiliary Transformer
1 Name & Place of Manufacturer Skipperseil Limited, India
2 Service Outdoor
3 Application/Designation
4 Reference Standards IEC 60076
5 No. of Transformers
6 MVA rating ( ONAF /ONAN ) MVA 12/10
7 Rated no load voltage ratio 11/6.9
8 Rated frequency Hz 50
9 Number of phases - 3
10 Current at rated no load voltage on principal Tap for HV & LV side Amp
11 Connections ( HV &LV windings ) - HV : DELTA , LV : STAR
12 Vector group Dyn11
13 Type of Transformer Neutral earthing
14 Type of Cooling ONAF/ONAN
15 Temperature rise over 40 deg C ambient
a) Top oil by Thermometer method Deg C 60
b) Windings by Resistance method Deg C 65
16 Hot spot temperature Deg C 20
17 Efficiencies at 75 Deg. C at Unity Power factor
a) at full load % 99.35
b) at 3/4 of full load % 99.46
c) at 1/2 of full load % 99.54
18 Efficiencies at 75 Deg. C at 0.85 Power factor
a) at full load % 99.24
b) at 3/4 of full load % 99.37
c) at 1/2 of full load % 99.46
MVA Loading corresponding to Maximum Efficiency at unity power
19 %
factor.
20 Maximum Efficiencies at 75 Deg. C at upf & 0.8 p.f. (lag) %
Regulation at full load at 75 deg. C at upf
21 % 0.91 & 5.65
& 0.8 p.f. (lag)
Total losses at rated voltage at Principal tapping & at rated frequency
22 kW 79
including auxiliary loss
23 Component losses
a) No load loss at rated voltage on principal tapping & at rated
kW 11 (±IEC Tol)
frequency
b) Load loss at rated current at principal tapping at 75 Deg. C excluding
kW 67 (±IEC Tol)
auxiliary loss
c) Auxiliary losses (Cooler loss) kW 1 (Max)
Impedance voltage at rated current at normal tap / minimum tap /
24 %
maximum tap
25 Reactance at rated current & rated frequency at Normal tap %
26 No load current at rated voltage and rated frequency %
Separate source power frequency withstand voltage Insulation level of
27 kV rms 28 & 20
HV & LV winding
28 Induced over Voltage withstand of HV & LV winding kV rms As per IEC
29 Full wave lightning Impulse withstand voltage of HV & LV winding kVp 75 & 60
30 Switching Impulse withstand voltage of HV & LV winding kVp As per IEC
31 Short circuit withstand current & Duration kA & sec
32 Permissible over loading As per IEC 60076-7
33 No. of radiators/ radiator bank 2
34 Rating of each radiator bank % 50
35 Type of Termination for HV & LV side Cable & Cable
36 HV Bushing
b) Type Oil Communicating Porcelain Type
c) Minimum Creepage distance mm 31
d) Rated Voltage Volts 12000
f) Lightning impulse voltage kVp 95
g) Power frequency withstand voltage kVrms 38
37 LV Bushing
b) Type Oil Communicating Porcelain Type
c) Minimum Creepage distance mm 31
d) Rated Voltage Volts 7200
f) Lightening impulse voltage kVp 60
g) Power frequency withstand voltage kVrms 20
38 LV Neutral Bushing
b) Type Oil Communicating Porcelain Type
c) Minimum Creepage distance mm 31
d) Rated Voltage Volts 7200
f) Lightening impulse voltage kVp 60
g) Power frequency withstand voltage kVrms 20
39 Oil quantity required for first filling Ltrs. 5000
40 Overall dimensions ( LxBxH ) mmxmmxm 5000 X 3800 X 5000 (in mm)(Approx.)
41 Max. flux density in core at tap which corresponds to
a) Rated voltage & frequency Tesla 1.72
b) 110% rated voltage & 100% rated frequency Tesla 1.892
c) 125% rated voltage & 100% rated frequency Tesla 2.15
d) 140% rated voltage & 100% rated frequency Tesla 2.408
42 Overfluxing withstand capability of transformer at
a) 110% rated voltage & 100% rated frequency sec.
b) 125% rated voltage & 100% rated frequency sec. As per IEC
c) 140% rated voltage & 100% rated frequency sec.
Resistance (at principal tap)per phase at 75 deg C winding temperature
43 ohm Will be provided DDE
of HV & LV winding

File Name : DATA SHEET 70,56 & 12 MVA Sheet 5 of 6

 Sl. No. Description Units Data
Amps/
44 Winding Current density of HV & LV winding ≤ 3.6 at Rated Tap
sq.mm
45 Vacuum withstand capability of tank
46 Thickness of transformer tank of side / bottom / top plates mm 5/8/10
47 Core
a) Material & thickness of core laminations mm 0.27
b) Type and thickness of insulation of core laminations Pressboard
48 Means adopted to prevent displacement of core in tank during
a) Transport from works to site
b) short circuits Will be provided DDE
c) Seismic disturbances
49 Conservator
a) Type Conventional
b) Type of oil preservation system -
50 CT particulars as applicable
a) Type Ring Type, Oil Immersed
HV : 700/1/1 A
b) Current ratio
LV : 1100/1/1 A
HV : PX/PX, Vk≤200v, Im≤ 30 mA
@Vk/2, Rct< 7Ω
c) Burden and accuracy class
LV : PX/5P20, Vk≤200V,Im≤30 mA
@Vk/2, Rct < 10 Ω
d) Short time withstand current in amps and duration in sec Will be provided DDE
51 Radiator
a) Overall dimension
b) Total weight with oil
c) Sheet steel thickness Will be provided DDE
d) Type of mounting
e) Vacuum withstand capability
52 Cooler Control Cabinet
a) Type Tank mounted
b) Panel material and thickness 2 mm CRCA
c) Degree of Protection IP55
53 Cooling Fans for each radiator bank
a) No. of working & standby fans 4 Working + 2 Standby
b) Motor rating kW 0.24
Time in minutes for which the transformer shall be run at full load
54 without exceeding permissible temperature when power supply to fans Will be provided DDE
is cut-off
57 Details of bushings (HV, LV & LV neutral )
a) Type Oil Communicating Porcelain Type
b) Voltage class kV 12, 7.2, 7.2
c) Power frequency withstand voltage (wet & dry) kV 38, 20, 20
d) Impulse withstand voltage kV 95, 60, 60
e) Creepage distance mm 31
58 HV Busduct Adapter box
a) Degree of protection
b) Phase to Phase Clearances mm Will be provided DDE
c) Phase to earth Clearances Mm
59 LV Cable Adapter box
a) Degree of protection
b) Phase to Phase Clearances mm Will be provided DDE
c) Phase to earth Clearances mm
60 LV Neutral Bushing Current transformers
a) Type Ring Type, Oil Immersed
b) Current ratio 1100/1/1 A
PX/5P20, Vk≤200V,Im≤30 mA @Vk/2,
c) Burden and accuracy class
Rct < 10 Ω
d) Short time withstand current and duration kA & sec Will be provided DDE
61 Radiator
a) Type & material
b) No. of radiators / bank
Will be provided DDE
c) Thickness of steel mm
d) Pressure withstand capacity kg / m²
62 Vacuum withstand capacity of main tank, radiators & accessories. mm of Hg 500
63 Tank details
a) Thickness of side plate Mm 5
b) Thickness of top plate Mm 10
c) Thickness of bottom plate Mm 8
d) Pressure withstand capacity kg /m²
e) Vacuum withstand capacity mm of Hg 500 mm
64 Minimum clearance height for lifting core and winding from tank mm 4500
65 Dimension/ Weight of transformer
a) Overall dimension L x W x H mxmxm 5000 X 3800 X 5000 (in mm)(Approx.)
b) Total weights kg 21700 (Approx.)
66 Oil quantity (NA) Litre 5000 (Approx.)
67 Marshalling box Degree of protection IP55
NOTE:- (1) All the weights & dimension are liable to change without affecting performance parameter.
(2) All the efficiencies & regulations are calculated at guaranteed No Load Loss, Load Loss & % Impedance at 75°C.
(3) Cables, Glands and Lugs are not in scope of Skipperseil Limited.

0 Base Submittal 29.05.23

Rev. Description Date Prepared By

File Name : DATA SHEET 70,56 & 12 MVA Sheet 6 of 6