Simulating Propagation Characteristic of UHF Signal for PD Monitoring in Transformers by FDTD Technique

Partial discharge (PD) in transformer can be detected on-line by UHF technique. However, the relationship between the UHF signal received by UHF sensors and the PD sources is not very clear. It is very important studying the propagation properties of the PD signal. In this paper, the electromagnetic waves emitted by PD sources are investigated. The finite difference time domain (FDTD) technique is used to model wave transients. The model consists of a tank and a PD source. The wave transients at different time and position are simulated. The results show the propagation transients of the PD signal in the tank and wave propagation attenuates with distance between the source and the sensors.