Surface Charge Accumulation Of Insulator In GIS And Its Online Monitoring Technology

In recent years, the technology of HVDC has been developed very fast and the level of the transmission voltage also has been raised gradually. The increased voltage requires the insulator to bear higher electric field so that the surface charge can accumulate on it. The Laplace field, at the beginning of design, would be changed when the quantity of surface charge accumulates too much, and that can lead to high electric field occur in some area on the insulator. What’s worse, that would cause flashover and power failure in power system. Therefore, studying the accumulation of surface charge and the online monitoring technology can enhance the stability of GIS.Firstly, this paper introduces the developing situation of GIS and the mechanism of the accumulation of surface charge on insulators. The accumulation of surface charge on insulators is mainly developed by the normal field of insulator in gaseous dielectrics.Secondly, based on the theory of unique electric field, the method of calculating electric field on the surface of the insulator with surface charge on it is created and an example is presented to show the method’s validity when surface charge exist on it. The influence of surface charge on electric field of insulator in GIS is shown through simulation with the improved method of calculating electric field. The distribution of electric field on the surface and the influence of flashover on it is analyzed when surface charge exist on concave or convex side of insulator.The theory of the online monitoring surface charge based on general probe method is created. In the present paper, finite element analysis software Ansoft is applied to build a simulation model of insulator in GIS. Using this model, suspended potential distribution on the surface of insulator is analyzed when it exist static charge and when it exist mental particle. The result shows that when static charge and mental particle existing on the surface of insulator in GIS, a obvious voltage signal would be produced on the fielding metal ring of GIS. Through measuring the voltage signal, the serious degree of the charge accumulation on the insulator can be known at any time.In this paper, the PSO is used for shape optimization of insulators. through optimization, the non-uniform field coefficient on the surface of insulator is reduced.