The function of voltage withstand test

Voltage withstand test, also known as high voltage dielectric strength test, is one of the main methods for testing the ability of electrical appliances, electrical equipment, electrical devices, electrical circuits, and electrical safety equipment to withstand overvoltage. Voltage endurance is divided into two types: AC voltage endurance test and DC voltage endurance test.  

AC withstand voltage test

AC withstand voltage refers to the highest voltage value that equipment can withstand when the voltage is positive or negative peak. The test voltage is more than one to several times the rated voltage of the tested equipment, and the AC voltage test equipment's withstand voltage is closer to the actual situation, without the need to gradually increase the voltage. From the perspective of thermal breakdown caused by dielectric loss, it can effectively discover local free defects and weak points of insulation aging. However, AC withstand voltage is more destructive to insulation than DC, and due to the fact that the test current is capacitive current, large capacity testing equipment is required.  

We can choose to useseries resonance testing equipment (also known as series resonance), power frequency withstand voltage testing equipment, and induction withstand voltage doubling equipment based on the capacity, voltage, current size, and electrical performance of the test sample. Conduct AC withstand voltage tests on large capacity equipment such as power cables, power transformers, high-voltage circuit breakers, and GIS composite appliances.

DC withstand voltage test

The DC withstand voltage test can detect local defects, moisture, and aging of insulation by measuring the leakage current values at different test voltages and drawing the leakage current voltage characteristic curve. Due to the voltage division based on insulation resistance under DC voltage, it is more effective in detecting end insulation defects than AC voltage. At the same time, due to the fact that insulation does not produce dielectric loss under DC voltage, the destructive effect of DC withstand voltage on insulation is minimal. Due to the fact that DC withstand voltage only requires a small leakage current, the required testing equipment has a smaller capacity.

We can choose DC high-voltage generators, portable voltage testers, and insulated glove voltage testing devices. Conduct DC withstand voltage test on equipment with small capacity for measuring zinc oxide lightning arresters.