Research On Creeping Discharge Phenomena Of Contaminated Glasses

With the continuous development of the power system in China, more and moresignificant role as one of the constraints of the safe operation of power system in China thecontamination flashover plays. The contamination flashover constraints insulation design oftransmission lines must be an important consideration. In the whole process of flashoverdischarge, the creeping discharge is the key factors to determine the minimum breakdo wnvoltage. Although flashover discharge in po lluted insulators has been researched andanalysed through a large number of experiments by domestic and foreign scholars, themechanism of surface discharge is still in the exploration stage of research. A unifiedconclusion which can be recognized by all has not yet formed. This paper summarizes theresearch results at home and abroad. on the basis of the results, this paper research thetip-board discharge phenomenon of contaminated glass through the experimental study andthe electric field computation, and conduct preliminary exploration to the mechanism ofthe creeping discharge on the polluted insulators. The main work and conc lusions of thispaper are as follows:(1) After conducting research polluted insulators, this paper designs the structure of thedischarge electrode and determines the material of the test prod uct, and then conducts acand dc pollution flashover experiment in this experimental device.(2) Under atmospheric pressure, the phenomenon of ac and dc pollution flashover on testproduct mainly contains three stages: the stable corona stage, the creeping discharge stage(transit from hardly frequent discharge in the be ginning to frequent discharge)and thebreakdown phase.(3) Under the ac voltage, the study found: the flashover voltage of the po lluted glasses isslightly higher than the flashover voltage of the clean glasses, but the leaka ge current of thepolluted glasses is much larger than the leakage current of the clean glasses. The abo vephenomenon is different from the phenomenon that the flashover voltage of the po llutedglasses is lower than the flashover voltage of the clean glasses, because our expe riments isconducted in short gap. (4) Under the dc voltage, the study found: when the gap is equal to1.2cm, the flashovervoltage of the polluted glasses is higher than the flashover voltage of the clean glasses;when the gap is equal to0.8cm, the flashover voltage of the po lluted glasses is less than orequal to the flashover voltage of the clean glasses. Thus the study found: the electrodestructure has a greater effect on the flashover voltage.(5) Under the experimental conditions of the same creepage distance, the minimumbreakdown voltage of polluted glasses under the negative dc voltage will decrease with theESDD gradually increasing. And under the experimental conditions of the same ESDD, theminimum breakdo wn voltage of polluted glasses under the negative dc voltage will risewith the creepage distance gradually increasing.The results above we achieved lay the foundation for the research on the influe nceof microstructure on the flashover of polluted insulators.