One novel type of UHF antenna for locating partial discharge and simulation of UHF signal propagation within transformer

In recent years, ultra high frequency (UHF) method has become a widely used method to detect partial discharge (PD) in transformers. For this method, we should pay attention to two crucial problems: (i) How to detect the UHF signals radiated from PDs; (ii) How to confirm the PD locations accurately. In this paper, a new type of antenna, named multi-element monopole antenna or Goubau antenna, is introduced to the area of PD detection. The antenna was designed using electromagnetic simulation software. The simulation software computed return loss shows a reasonable agreement with tested data. Both of the results turn out that operating frequency range of the antenna is about 400-1000MHz. To study the influence brought by inner structures of transformer, the time-delay effects caused by core and winding respectively were simulated using FDTD method. It is concluded that time-delay effect caused by core is obvious, while the effect caused by winding is not.