Wuhan UHV specializes in producingseries resonance (also known as AC/DC withstand voltage test device). Next, we will share with you the principle of AC/DC withstand voltage test device.

Principle of AC/DC voltage withstand test device

Scope of application: AC withstand voltage test for various power equipment. The basic principle of the frequency conversion series resonance test device is to use an adjustable (30-300Hz) series resonance test equipment to resonate with the tested capacitor to generate an AC test voltage. The working power supply is single-phase 380/220V ± 10%, 50Hz.

Series resonance, series resonance test device, frequency conversion series resonance test device, functions and characteristics

1. Frequency modulation tuning method. The fixed inductance reactor is used to achieve resonance in the test circuit by adjusting the frequency of the excitation power supply. Its characteristics are small size, light weight, high quality factor, and easy to use. It has gradually replaced the inductive type.

2. Series resonance series resonance test device Variable frequency series resonance test device has a wide range of applications. The entire set of variable frequency series resonant high-voltage testing equipment fully complies with the relevant national regulations and requirements for high-voltage testing, and is suitable for high-voltage and large capacity power equipment, such as generators, large transformers GIS、 AC voltage withstand test for cross-linked polyethylene power cables, high-voltage switches, transformers, etc.

3. Modulation wave principle. Series resonance is a resonant current filtering circuit that can improve the distortion of the power supply voltage waveform, obtain a good sine voltage waveform, and effectively prevent the damage of harmonic peaks to the test sample.

4. Overcurrent situation during detuning. 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 one tenth (1/Q) of the normal test current. Compared with conducting voltage withstand tests using parallel resonance or test transformer methods, series resonance voltage withstand can effectively identify insulation weaknesses without the risk of large short-circuit current burning the fault point.

5. Overvoltage situation when the frequency conversion series resonance test device loses resonance. When the test sample experiences flashover breakdown, due to the loss of resonance conditions, in addition to the immediate decrease in short-circuit current, the high voltage also disappears immediately, and the arc is extinguished immediately. And the resonance voltage takes a long time to establish again, making it easy to disconnect the excitation power supply before reaching the flashover voltage again. Voltage recovery is an intermittent oscillation process of energy accumulation, which is long and does not result in any recovery overvoltage.