Disadvantages:
Compared with test transformers, they are more expensive, especially for equipment such as transformers, bushings, gis, reactors, cables, capacitors, transformers, etc. Transistor sine wave series resonant power supply without partial discharge withstand voltage test.
Advantages:
1. The required power supply capacity is greatly reduced. The series resonant power supply uses the resonance of the resonant reactor and the capacitance of the test product to generate high voltage and large current. In the entire system, the power supply only needs to provide the active power consumption part of the system. Therefore, the power supply power required for the test is only the test capacity. 1/Q.
2. The weight and volume of the equipment are greatly reduced. In the series resonant power supply, not only the bulky high-power voltage regulating device and the ordinary high-power power frequency test transformer are eliminated, but also the resonant excitation power supply only needs 1/Q of the test capacity, which greatly reduces the weight and volume of the system. Generally, 1/3-1/5 of ordinary test equipment.
3. Improve the waveform of the output voltage. The resonant power supply is a resonant filter circuit, which can improve the waveform distortion of the output voltage, obtain a good sinusoidal waveform, and effectively prevent the harmonic peak from accidentally penetrating the test product.
4. Prevent large short-circuit current from burning the fault point. In the series resonance state, when the insulation weakness of the test sample is broken down, the circuit is immediately detuned, and the loop current rapidly drops to 1/Q of the normal test current. When doing a withstand voltage test using parallel resonance or test transformer methods, the breakdown current immediately rises dozens of times. Compared with the two, the short-circuit current and breakdown current are hundreds of times different. Therefore, series resonance can effectively find insulation weaknesses, and there is no worry of large short-circuit currents burning fault points.
5. There will be no recovery overvoltage. When the test sample breaks down, the high voltage will disappear immediately due to the loss of resonance conditions, and the arc will be extinguished. Moreover, the re-establishment process of the recovery voltage is very long, and it is easy to disconnect the power supply before reaching the flashover voltage again. This kind of voltage The recovery process is an intermittent oscillation process of energy accumulation, which is long and does not cause any recovery overvoltage.