Analysis of ice-melting insulated ground wire influence on substation grounding safety

In order to directly melt ice accumulated on ground wire with direct current (DC), ground wire shall be transformed into insulated one. Erection mode of ice-melting insulated ground wire changing distribution of short-circuit current among substation grounding net has effect on substation grounding safety. Model of substation with insulated ground wire under short-circuit fault is built using ATP-EMTP simulation software. Influence of erection mode of ice-melting insulated ground wire on substation grounding safety is investigated, and improvement measures for substation grounding safety is recommended. Research results show that erection mode of ice-melting insulated ground wire will cause increase of grounding net shunt coefficient, and affect substation grounding safety. Grounding net shunt coefficient is affected mainly by substation grounding resistance and number of transmission lines coming in and out of the substation. For substations with grounding net shunt coefficient less than 50%, after erection of ice-melting insulated ground wire, step voltage and touch voltage of grounding net should be checked again. Safety performance of grounding net is improved due to insulated ground wire near substation grounding, and optimal number of grounding towers are 6 to 8. © 2015, Power System Technology Press. All right reserved.