Experimental Study on the Relationship between Partial Discharge and Gas Decomposition Products in SF_6 Insulated Electrical Equipments

摘要

SF_6 decomposition serves as an effective means for online fault detection and diagnosis of SF_6 insulated equipments. The relationship between SF_6 decomposition products and partial discharge (PD) in SF_6 insulated equipments remains a significant theoretical and practical issue to be addressed. Based on the simulations of protrusion discharge, floating discharge and surface discharge in SF_6 insulated equipments, the present experiment studied the impacts of differentiated PD patterns, PD severities and SF_6 pressures on the concentrations of SF_6 decomposition products as well as the change in concentrations over time. The experimental results indicate that three kinds PD pattern discharges produce SOF2+SO_2 and HF, the concentration of the SOF_2+SO_2 being always higher than HF. Generation of both gases increase with voltage application time; The concentrations of SOF2+SO_2 and HF differ from differentiated PD discharge strength, and increase as discharge strength ascends; A negative relationship exists between SF_6 gas pressure and the generation speed of SOF_2+SO_2 and HF. It is concluded that SF_6 decomposition products, SOF_2+SO_2 and HF in particular, could be used as a means for on-line PD faults detection and diagnosis.