Characterisation of Microstrip patch antenna based UHF sensor for detection of partial discharge

Major Prerequisite to overcome the problem due to the insulation breakdown in High Voltage (HV) power apparatus is the efficient diagnosis of partial discharge (PD). Many different methods have been proposed by researchers for detection and measurement of PDs in past, based on different outcomes of PD such as Chemical, Acoustic, Electrical, Optical and Electromagnetic (EM) wave radiation. Among these, detection of PDs by EM wave in the Ultra High Frequency (UHF) range could be an efficient method, as it is a noncontact type measurement method for PD detection. PD pulses are having life span of several nano-seconds, which can be detected by suitable wide bandwidth (BW) UHF sensor. In this work, a wide BW Microstrip patch antenna has been designed for detection of radiated EM wave in the UHF band due to PD activities in high voltage power apparatus. The proposed antenna is cost effective and having specific center frequency, capable of rejection of surrounding noise. PDs obtained from a model transformer presented here for characterizing the proposed sensor, made of Microstrip patch antenna. The characterization of the sensor has been presented by varying the PDs in the model transformer and also the distance of the sensor from PD source. The experimental result shows that the designed sensor having good sensitivity and can be used to detect PDs at a distance up to fifteen meters from the source of PDs. It is a cost effective and reliable tool for PD detection in HV power apparatus.