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
