Study of anti-interference technology for UHF PD-detection in power transformers

In this paper, the anti-interference technology for UHF PD-detection in power transformers is described. When we detect PD on power transformers using an UHF PD online monitoring system made by us, several kinds of interference signals are found in substations in China. The interference signals may cause that the sensitive of the measuring system get lower and the system give out a wrong indication. The interference signals include GSM mobile signal, TV and communication and some other signals with certain frequencies, partial discharges of other power equipments that are near the equipment to be measured. According to the characteristic of the interference signals, the solving methods are found to avoid to be influenced during the measurement. The new UHF PD online monitoring system with the methods of anti-interference can get rid of every pulse that is not created by the power transformer to be measured. The results show the methods are available and effective.