Partial discharge detection test voltage The state of the sample and the environmental conditions In order to make the test results authentic, the various conditions required for the test must meet the due requirements, so as not to get false results.

Partial discharge detection test voltage

Under AC voltage, the voltage value applied in the partial discharge test refers to the effective value (peak value divided by √2). The AC power supply voltage should be a sine wave, and there should be no excessive high-order harmonics, because the high-order harmonics have an impact on the discharge mechanism, and the measured values will be different at this time; at the same time, if the high-order harmonic resistance value If it is too large, it will directly cause errors in the measurement readings. The partial discharge detector uses a moving coil voltage regulator to regulate the voltage, which is often prone to large distortion of the waveform and a large amplitude of high-order harmonics, which should be noted. Therefore, higher harmonics in the power supply should be limited to less than 10% and sufficiently unindicated at the required sensitivity.

The state of the test object

There are many kinds of test samples, each with its own special insulation treatment method, so each test sample must complete the insulation treatment process before the test. In general, the surface of the test object should also be kept dry and clean, since moisture and dirt on the surface of the test object can cause partial discharges on the surface.

In order to ensure the repeatability of the test results, the following issues should be paid attention to before the partial discharge detector test:

The electrical, mechanical and temperature conditions of the test product should be good and stable;

Due to the effect of voltage hysteresis, for at least a few hours before the test, do not withstand a voltage exceeding the specified maximum value of the partial discharge test voltage;

Partial discharge detection ambient conditions

There is a large enough test site to meet the requirements of the test voltage, and the electric field around the test object should not cause significant distortion. Appropriate distances should also be maintained between the sample and its surroundings. No other messy objects should be stored in the test area. There should be no messy metal pieces (such as bare copper wire segments, screws, nuts and other small metal pieces, etc.) on the ground of the high-voltage line.