Partial discharge refers to the non-penetrating discharge that occurs between the electrodes of the insulating medium in the high-voltage equipment under the action of high electric field strength. This kind of discharge only exists in the local location of the insulation, and does not immediately form a penetrating channel, so it is called For partial discharge. The partial discharge detector can effectively detect the partial discharge value of high-voltage equipment.

Using a partial discharge detector is just a tool, so how can we effectively judge whether the partial discharge value meets the standard?

(1) A large number of laboratory simulations and on-site test results show that the phase of the partial discharge signal and the phase of the test power supply have a phase characteristic of 180 degrees or 360 degrees, and occur at a certain width of the phase at the same time.

(2) If multiple signal sources are found during the test, bandpass filters should be used to extract pulse signals of different frequency bands for separate analysis;

(3) Whether the waveform and frequency spectrum of the high-frequency pulse signal collected by the partial discharge sensor have typical partial discharge characteristics (the rising edge of the pulse waveform is generally tens of nanoseconds);

(4) When necessary, repeat the analogy between the actual test partial discharge waveform and the waveform when the test loop is calibrated with the analog partial discharge source to observe the similarity of the signal;

(5) Polarity discrimination method: use the polarity of the pulse waveform to identify the position of the partial discharge source;