The study on the arrangement of UWB RF sensor-array for the PD location in transformers

Ultra-Wideband (UWB) Radio Frequency (RF) PD location technique is a new method, which is based on diamond shape sensor array PD detection and time-delay function. In this paper, an UWB RF PD location system is designed, which works in the bandwidth of 2GHz-8GHz. The time-delay error has been brought down to 0.3ns. but the locating error of some PDs is larger than 30cm. To make clear this problem and solve it, the location errors of PD sources lying in transformer are calculated using diamond shape sensor array. The results indicated that the PD sources lying to the side of the sensor array cannot be located exactly. To solve this problem, we designed another sensor array and installed it on the side of transformer. PD locating experiments are carried on a 220kV transformer. The results confirmed the location accuracy of the new sensor array.