The influence of low and zero resistance insulators on the voltage distribution of insulator strings

Under the long-term effects of electrical load and nature environment factors, the insulators' insulation properties will gradually decline, and the low and zero resistance insulators will appear in the insulator strings. As the existence of low and zero resistance insulators could cause great danger to the safe operation of power system. The influence of low and zero resistance insulators on the voltage distribution of insulator strings for 500kV transmission lines is analyzed in this paper. To obtain the influences that the low and zero resistance insulators exerts on voltage distribution of insulator strings, the circuit model of 30 pieces of insulator strings for 500kV transmission line is simulated and analyzed by MATLAB. The simulation results show that there is no direct correspondence between the two methods to judge the insulators with low and zero value. If the insulation resistance of low and zero resistance insulators decrease to 30Mn, its own distribution voltage drops about 50%.