66kV Oil-immersed Power Transformer

Economic or deluxe solution optional Better cost performance IEC Standards Criteria New factory for better price NVTC/ OLTC

REFERENCES

ISO 1461: Hot dip galvanized coatings on fabricated iron and steel articles – Specifications and test methods.

IEC 60076: Power transformers.

IEC 60044: Instrument transformers.

IEC 60296: Specification for unused mineral insulating oil for transformers and switchgear.

IEC 60354: Loading guide for oil – immersed power transformers.

IEC 60214: Tap-changers - Part 1: Performance requirements and test methods, Part 2: Application guide.

IEC 60512: Connectors for electronic equipment.

Performance

66kV Two-Winding Power Transformer With NVTC/OLTC
Rated Capacity (kVA)	Rated Voltage (kV)			Vector Group	Losses (W)		Impedance Voltage (%)
	HV	Tapping Range	LV		No load	On load
630	63 66 69	±5%	6.3 6.6 10.5 11	Yd11	1360	7560	8.0
800					1620	8830
1000					1920	10440
1250					2260	12340
1600					2720	14850
2000					3200	17550
2500					3760	20700
3150				YNd11	4480	24300
4000					5280	28800
5000					6240	32400
6300		±2×2.5%			8000	36000	9.0
8000					9600	42750
10000					11360	50400
12500					13360	59850
16000					16080	73530
20000					19040	89100
25000					22480	105300
31500					26720	126900
40000					32000	148950
50000					37760	184500
63000					44880	222300

 INSULATION LEVELS

Nominal system voltage (kV,   rms)	Highest system voltage (kV,   rms)	Lightning Impulse withstand voltage, dry (kV,   peak)	Power frequency withstand voltage, wet (kV,   rms)
33	36	200	95
132	145	650/750 (internal/external)	275/325 (internal/external)

AUXILIARY SUPPLIES

Equipment generally rated for the following auxiliary power supplies:

(a)          Cooler control circuits:          220V, 240 V, single phase, 50Hz

(b)         Tap changer control:              220V, 240 V, single phase, 50Hz

(c)          Cooling fan motors:               380V, 415 V, three phase, 50Hz

(d)         Tap changer motor:               380V, 415 V, three phase, 50Hz

 

 ROUTINE TEST to IEC 60076 (to be done during acceptance testing at factory)

• Measurement of winding resistance

• Ratio test

• Vector group

• Separate source voltage withstand test

• Induced over-voltage

• Insulation resistance

• Oil leakage test on fully assembled transformer for 12 hours

• Measurement of impedance voltage

• Magnetic balance

• Measurement of no-load loss and current

• Measurement of load loss (at normal & extreme taps)

• Tests on on-load tap-changer

• Tests on on-load tap-changer remote control panel

• Efficiency at 50%, 75%, 100% loading at unity p.f and rated terminal voltage (Corrected to 75C)

• Lightning impulse withstand test

Type Tests to IEC 60076 (to be done during acceptance testing at factory)

• Temperature rise test – To be performed on one unit during acceptance testing.

Lightning Impulse Withstand Test is already listed under Routine Tests as per IEC 60076.

Test Facility

66kV Oil-immersed Power Transformer