Research On The Influence Of Space Charge Caused By Corona Discharge To Gap Discharge

Corona discharge phenomenon exists widely in electric power system. Coronadischarge can be caused by various insulation problems in the manufacture or operation ofthe Power equipments under high DC voltage， and it also exists in high voltagetransmission lines near the wire or thundercloud near the tip of the electrostatic fieldobjects. Corona discharge which subject to continuous DC voltage will produce a lot ofspace charge， mainly for a large number single-polarity space charge accumulated in itsion migration areas. According to the gas discharge theory， this space charge backgroundmay affect the insulating properties of air gap. Therefore， studying the influence on theair gap insulation performance from the Background of space charge made by the Coronadischarge Can not only provide further reference for more in-depth research on gasdischarge mechanism， but also have very important practical significances on choosingthe air gap spacing in the power system reasonable， improving the insulation of theexternal insulation structure and exploring new insulation technology.This paper stated revalent research and experiments on corona discharge based on thebackground of space charge characteristics of corona discharge and its influence on air gapinsulation. It analyzed the space charge characteristics of corona discharge and thepossible impact of gap insulation performance through the theory of gas discharge at first.Then it designed the experiment scheme to compare the different polarity and differentconcentration under the background of space charge effect on the properties of insulationboard clearance. The results of the series of experiments showed: positive space chargeproduced by the corona discharge under the condition of continuous high positive DCvoltage could inhibition the development of discharge process in the air gap and improveU50%， on the opposite， negative space charge produced by the corona discharge underthe condition of continuous high negative DC voltage could promote the development ofdischarge process in the air gap and reduce U50%， the effect became more obviously with the increase of concentration of space charge until the space charge decreased to acertain degree on which the basic process of discharge gap didn’t make a difference. Thispaper finally analysised the results of the experiments which thought Space chargebackground on the influence of the initial electrons is the most important reason whyU50%in the air gap changed.