When the field strength generated by the applied voltage in the electrical equipment is enough to cause the discharge in the insulated part of the area, but the discharge phenomenon does not form a fixed discharge channel in the discharge area, it is called partial discharge.

The principle of the digital partial discharge detector is the pulse current method:

The pulse current method means that when a partial discharge occurs, the two heads of the sample Cx make an instantaneous voltage change Δu. At this moment, if the electrical Ck is coupled to a detection impedance Zd, a pulse current I will be generated in the loop, and the pulse current will be generated through the detection impedance. By detecting, amplifying, and displaying the pulse voltage information of the pulse voltage information, some fundamental parameters of the partial discharge can be measured (the first is the discharge quantity q).

What needs to be pointed out here is that the actual partial discharge volume inside the test product cannot be measured. Because the transmission path and direction of the partial discharge pulse inside the test product are messy, we only need to pass the comparison method to test the visual appearance of the test product. Discharge charge, that is, before the test, inject a certain amount of electricity into both ends of the sample, adjust the magnification to establish a ruler, and then compare the partial discharge pulse inside the sample received under the actual voltage with the ruler to obtain the test The apparent discharge charge of the product.

The digital partial discharge detector ensures the reliability of the detected data through interference signal processing methods such as digital signal processing and adaptive filtering.