The Investigation Of High Speed Grounding Switches On Secondary Arc In 800kV GIS

This paper mainly presents the mechanism theory of secondary arc current generated in ultra-high-voltage (UHV) power transmission system and method of how to suppress it. The amplitudes of secondary arc current and recovery voltage are two decisive factors to extinguish secondary arc. The extinction of secondary arc is necessary condition to single-phase auto reclosure. At present, the investigation of secondary arc is still in exploratory development period, which does not come into being the perfect theories, and that secondary arc current and recovery voltage relate to whether to the extinction of secondary arc, which successfully bring the single phase auto-enclosing, having the extremely important meaning to the maintain stability of power system. Recently, the voltage grades of 750kV and 1000kV UHV lines are being researched all over the world and it has already been put into production in some district. On EHV/UHV lines secondary arc is a key factor, the higher the voltage grade is, the severer the influence is. Therefore, it is necessary to have a further analysis and research to the secondary arc current and recovery voltage.The amplitudes of secondary arc current and recovery voltage are calculated in this paper, it firstly draws circuit diagram of capacitance and inductance, then simulates the whole circuit by MATLAB. The single-phase earth faults is imitated by a switch, the opening or close of this switch is controlled by a timer, we can observe the dynamic wave of the secondary arc current when switch is closed and the dynamic wave of recovery voltage when switch is opened. By calculation and simulation, it can obtain the relation of secondary arc current, recovery voltage and the position of fault pot. Finally, the method of suppressing secondary arc is put forward.Presently, there are two key methods of suppressing secondary arc, one is the neuter node of shunt reactor being connected to the small reactor;the other is installing high speed grounding switches (HSGS) on both ends of the lines. This paper adopts the latter method, in order to meet the request of making secondary arc, specific designed contents are as follows: the system of contactor of HSGS;calculating pressure, electrodynamic of contactor and the opendistance. In order to satisfy the request of speed, the operating machine which is suitable with HSGS is chosen;drawing the whole configuration figure of HSGS.Moreover, the paper also refers to other measures of suppressing secondary arc, for instance series capacitor etc. This paper expatiates on the working theory of several methods, and simply compares their advantages and disadvantages as well.