Detection and Analysis of Partial Discharge using Ultra High Frequency Sensor

Partial Discharge (PD) measurement is a precise diagnosis to give the knowledge about the condition of the insulation. There are several methods to detect and measure the PD such as Electrical, Acoustic, Optical, Chemical and Ultra High Frequency (UHF) detection methods. Among all these methods, UHF sensor plays crucial role to detect the PD, efficiently with high sensitivity. PD pulses tend to appear only in the time of nano-seconds, which pulses can be detected without any power outage by using high bandwidth antenna i.e. UHF sensor. UHF sensor is conical in shape with base diameter 2.5cm and axial length 10cm. This sensor can detect the electromagnetic interference signals without any background noise in the range of 300 MHz to 1.5 GHz. In this paper, the experimental work was presented to study the characteristics of PD by using the designed UHF conical monopole antenna with the help of high bandwidth digital oscilloscope connected through co-axial cables in two distinct lengths. FFT analysis was applied to deduce the frequency response of the PD signal and sensitivity of the antenna.