INFLUENCE OF INSULATOR SHED ON STREAMER PROPAGATION ALONG INSULATION SURFACE

摘要

The flashover of insulators is one of important problems in the design and operation of transmission lines. The streamers formation and subsequent propagation is an important precursor to flashover in air gap and over insulation surfaces. Therefore, the comprehensive study of the interaction of the insulation surface with the streamer development process is usefull to improve the indoor and outdoor the insulation performance. Experiments were carried out in a three electrode arrangement consisting of a parallel-plane gap (10 cm), stressed by negative DC voltage. Streamers were initiated from a sharp point which was set in a shaped receptacle at the center of the lower grounded plane and propagated along the silicon rubber insulator surface. The electric field required for stable streamer propagation and the propagation velocity with electric field sustaining stable streamer propagation were studied. The influence of insulator shed on streamer propagation along silion rubber insulation surface was investigated. The conclusion was that the electric field required for stable streamer propagation and the associated velocity increased/decreased with the rise of the protrusion length of insulator shed.