Experimental Study Of Interference Suppressing For On-line Partial Discharge Measuring In Transformer

According to the project of on-line monitoring PD in transformer, the directional sensors have been developed. The directional sensors consist of a closed coil and an unclosed coil. The characteristic of the sensors has been studied by the experiment. The experimental results show that there is a certain relationship between their sensitivity and the value of damping resistance & the circle number of coil. It has proved by the experiment that the response characteristics of the directional sensors are suitable for the measuring system.On the basis of the theory and the experiment, the paper has synthetically analyzed the anti-interference characteristics of the hardware method (differential balance) and software method (digital filter) .The paper has presented that these two methods have some disadvantages respectively. Based on this fact, a new method has been presented. Hardware method can be use to restrain periodical interference, and software method can be use to discriminate pulse polarity. The experimental results show that the method can suppress periodical interference and distinguish partial discharge from interference.