Partial Discharge-Free Power Frequency Withstand Voltage Test System  Meets the AC withstand voltage and partial discharge testing requirements for transformers, GIS, instrument transformers, and other equipment at the 110kV and 220kV voltage levels. For the 220kV voltage level, the maximum test voltage is 460kV; for the 110kV voltage level, the maximum test voltage is 275kV, with a withstand duration of 1 minute.

Partial Discharge-Free Power Frequency Withstand Voltage Test System System Features

A hydraulic lifting system enables one-touch operation to switch the main unit between a horizontal position (for transport) and a vertical position (for operation).

The system primarily consists of an operation console, a test transformer, a high-voltage measuring voltage divider, a coupling capacitor, a current-limiting reactor, a low-voltage compensation reactor, a power isolation transformer, and other components.

①   Strong arc-extinguishing capability and superior insulation performance.

②   Fire-resistant; utilizes non-flammable gas for intrinsic safety.

③   Lightweight with a highly integrated structure, combining the gas-insulated test transformer, coupling capacitor, current-limiting resistor, and voltage divider into a single unit.

④   Convenient for transport and installation; requires minimal floor space.

⑤   Clean and oil-free; requires no maintenance (only periodic monitoring of gas pressure and density is necessary).

⑥   Minimally affected by environmental conditions, as the entire system is hermetically sealed within a metal enclosure.

⑦   Traditional configuration (with external current-limiting resistors, coupling capacitors, and voltage dividers): Partial discharge level is approximately 10pC.

⑧   Integrated configuration (with built-in current-limiting resistors, coupling capacitors, and voltage dividers): Total partial discharge level is 5pC.

⑨   Partial discharge level: < 5pC. Protection functions: Over-current and over-voltage protection with alarm and automatic return-to-zero capability.

Main Technical Parameters and Functions of the Device

1. Rated Capacity: 250 kVA
2. Input Power Supply: Single-phase 380 V, 50 Hz
3. Rated Voltage: 500 kV
4. Rated Current: 0.5 A
5. Operating Frequency: 50 Hz
6. Device Output Waveform: Sine wave
7. Waveform Distortion Rate (Complete Set): ≤ 2%
8. System Noise Level: ≤ 50 dB
9. Transformer Short-circuit Impedance: ≤ 10%
10. Operating Duration: Continuous operation permitted for 30 minutes at rated voltage and current; 1 minute at 1.1 times the rated voltage (overvoltage).
11. Partial Discharge Level (Complete Set): ≤ 5 pC at rated voltage.
12. Test System Protection:

(a) To mitigate the impact of overvoltage generated on the test transformer during test object discharge, appropriate protective resistors are configured within the high-voltage circuit, and other supplementary protective measures are also implemented.

(b) The high-voltage side employs a tail-end current-based overcurrent protection device, as well as other effective protective mechanisms.

13. Dimensions and Weight

(1) Total Length: 7.4 m

(2) Total Width: 1.54 m

(3) Horizontal Height: 2.8 m; Vertical Height: 6.2 m

(5) Total Weight: 5.6 t