Experimental Study on the Effectiveness of Partial Discharge Detection in Switchgear Based on Non-contact UHF sensing

Partial discharge (PD) defect is a common defect in high voltage switchgear, which seriously affects the safety and stability of distribution network. The sensitivity and effectiveness of the commonly used PD detection technology such as TEV and AE have been greatly affected due to the good sealing performance of switchgear. A new PD detection technology is proposed in the paper, an ultra-high frequency current sensor (UHFCT) is pass through the live displaying device of switchgear, to couple high frequency transient signals in the electrical circuit. A test platform based on live displaying device is set up and typical PD defect is made. UHFCT, high frequency current sensor (HFCT), detection impedance and ultra-high frequency (UHF) antenna are used for PD detection. It’s found that all kinds of detection methods can detect PD signals, UHFCT detection results have relatively large amplitude, only smaller than that of impedance. UHFCT adopts non-contact penetrating sensing technology, which does not affect the original electrical circuit of switchgear. Its effectiveness has been well verified and it can be widely used.