Partial discharge is mainly used to check whether large-scale electrical equipment has local defects in the discharge source. With the increasing voltage level and capacity of the power system, the measurement of partial discharge of transformers has received more and more attention from large-scale power transformer operation and management units. It is one of the important indicators to determine the reliability of the insulation system. In addition, the partial discharge tester can also analyze whether there is an area with excessive dielectric strength inside the transformer, and effectively reduce the hazards that can be caused by the long-term safe operation of the transformer. Partial discharge of transformers can be used for power transformers, transformers, lightning arresters, etc.

Transformer partial discharge test

First of all, the partial discharge test should be performed in a special shielded room. The special shielding device can effectively shield the external interference signal. If you use it on site, we need to pay attention to many details. For example, the field electromagnetic interference is very large and grounded. Conditions, noise, etc., may affect the results of the partial discharge test.

Before the measurement, we still have to power off some electrical equipment, and then measure the ground resistance with a large grounding resistance tester to ensure that the ground resistance is very good. If the conditions are not suitable, it is recommended to measure the partial discharge in the middle of the night, so that the voltage is relatively stable , Electromagnetic interference is relatively small. Of course, this is only a relatively common way to deal with interference. If on-site interference is not enough, it is recommended to add a shielded room.

Several factors of partial discharge

The electric field is too concentrated at a certain point; b. The solid medium has bubbles and harmful impurities have not been removed; c. The oil contains water, gas, and suspended particles; d. In different medium combinations, there are serious electric field distortions at the interface.