Measurement of Partial Discharge in Air Insulation by using UHF Double Layer Bowtie Antenna with Modified Wings Edges

The measurement of partial discharge (PD) by detecting the released energy from the PD source in the form of electromagnetic wave during the corona discharge(discharge in air) by using Ultra-High Frequency (UHF) antenna has been an accurate diagnostic technique to determine the condition and quality of the insulation system in high voltage equipements. The UHF sensors have shown a great advantage in the detection of partial discharge because they are capable to detect partial discharge signal online without the need of prior shutdown of the high voltage apparatus. This paper discuss the measurement of partial discharge in air insulation by using the designed UHF double layer bowtie antenna with modified antenna wings edges. The double layer bowtie antenna was used to detect PD based on EM waves induced by PD in air insulation. The PD measurement results obtained by using the designed double layer bowtie were compared with PD measurements results obtained by using the RC detector which was taken as a comparison sensor. The characteristics of PD induced EM waves measured by RC detector and double layer bowtie have been investigated. The PD measurement was performed at three applied voltage levels namely, 5 kV, 6 kV and 7kV. The PD measurement results have shown that the higher applied voltage, the high Vpp magnitude for PD waveform, PD charge magnitude and PD number in both negative and positive half cycle.