Simulation Study On Pre-Arcing Time-Current Characteristic Of High-Voltage Current-Limiting Fuse

High-voltage current-limiting fuse is able to break big short circuit and limit current effect significantly. It is widely used in supply and distribution system in urban as the most important product of transformers in over-current protection. In particular, combined electrical apparatus which combine fuse with the high-voltage load switches and the contactors could take place of the high-voltage circuit breakers which is expensive in short circuit small capacity networks.In recent years, the accidents of pipe exploding and malfunction caused by fuse protection happen frequently, which make a great damage to the power system and the power supply equipments. In order to make the fuse cooperate with other protection devices preferably, the simulation of pre-arcing time current characteristics was obtained in this paper. It also supplies a foundation for the design of the full range fuse in the future.In this paper, pre-arcing time of the high-voltage current-limiting fuse was calculated by using finite element ANSYS. The temperature fileds during the short circuit current and the overload current were simulated separately. Through the analysis of pre-arcing mathematical model of current-limiting fuse, the 3 dimensions electric-heat coupling mathematical model of breaking short current under the AC cold state was proposed and the material physical parameters varying with the temperature was considered. Pre-arcing time was the process of fuse melt. With the decrease of the short current, the time of boiling was considered. So the simulation results is more precise. Through simulation we can get pre-arcing time when the DC of short circuit current is max, the simulation results show that this method is in common use.For the scarcity about the analysis method on pre-arcing time of fuse under overload current, the model was proposed, based on the electric-heat coupling mathematical model under the short current, and the phase change was taken into account. The problem of latent heat was solved by the enthalpy method. For breaking low overload current, because pre-arcing time of is much longer, the heat dissipation of surrounding quartz sand should be considered. In this paper, using equivalent DC method replaced AC. The mathematical model under low overload current was presented. Pre-arcing time were calculated by the simulation.In this paper, the backup protection high-voltage current-limiting fuse was taken as the research object, which rated current is 200A. The simulation results of pre-arcing time under 4-35 fault current have been achieved. Finally, pre-arcing time-current curve was combined. The comparisons between the simulation results and the manufacturer data were gained which prove the feasibility of the method.