Series resonant withstand voltage equipment

Product Introduction

The cable AC withstand voltage test device mainly consists of a variable frequency power supply, excitation transformer, resonant reactor, and capacitive voltage divider. The equipment is suitable for AC withstand voltage testing of 10kV, 35kV and other cables. The frequency adjustment range of the HNXZ series cable AC withstand voltage testing device is 30-300Hz, which complies with the enterprise standard "Preventive Test Regulations for Power Equipment" issued by Southern Power Grid Corporation. It not only meets the withstand voltage requirements of high-voltage XLPE cables, but also has the advantages of light weight and good mobility, making it suitable for on-site testing.
Product features
1. The required power capacity is greatly reduced. Series resonant power supply generates high voltage and high current through resonance between resonant reactor and the tested capacitor. In the entire system, the power supply only needs to provide the active consumption part of the system. Therefore, the required power supply for the experiment is only 1/Q of the test capacity.
2. Improve the waveform of the output voltage. A resonant power supply is a resonant filtering circuit that can improve the waveform distortion of the output voltage, obtain a good sine waveform, and effectively prevent the accidental breakdown of the test sample by harmonic peaks.
3. The weight and volume of the equipment have been greatly reduced. In a series resonant power supply, not only is the bulky high-power voltage regulating device and ordinary high-power power frequency test transformer eliminated, but the resonant excitation power supply only requires 1/Q of the test capacity, greatly reducing the system weight and volume, usually 1/10-1/30 of ordinary test devices.
4. Prevent large short-circuit currents from burning the fault point. In the series resonance state, when the weak point of the insulation of the test sample is broken down, the circuit immediately loses resonance, and the loop current rapidly drops to 1/Q of the normal test current.
5. There will be no overvoltage recovery. When the test sample breaks down, due to the loss of resonance conditions, the high voltage immediately disappears and the arc immediately extinguishes
Technical Specifications
（1） Main parameters:
1. Rated output voltage 0-220 kV (AC RMS) and below
2. Output frequency 20-300Hz
3. Frequency regulation fineness 0.1Hz, instability ≤ 0.01%
4. Resonant voltage waveform sine wave, waveform distortion rate ≤ 1%
5. Full load working time, continuous working time of 60 minutes
6. System quality factor ≥ 20 under maximum load
7. Working power supply 380V ± 10% three-phase or 220V ± 10% single-phase (below 10kW), power frequency 50Hz ± 5%
（2） Technical specifications of HNXZ-270kVA/270kV/45kV variable frequency series resonance test device
1. Rated voltage:
45kV - meets the AC withstand voltage test of 10kV cables;
90kV - meets the AC withstand voltage test of 35kV cables;
135kV - meets the AC withstand voltage test of 110kV cables;
270kV - meets the AC withstand voltage test of 110kV substation switches;
2. Distortion rate of output voltage waveform:<1.0%
3. Allowable continuous working time: work for 5 minutes at a time under rated conditions;
4. Quality factor of the device itself: Q>50
5. GIS， Quality factor of switch and other tests at full load: Q>50 (load dependent)
6. Input power supply: single-phase 380V
7. Frequency adjustment range: 30Hz~300Hz
8. System measurement accuracy: 1.5%
9. The device has protection functions such as overvoltage, overcurrent, and zero start