Insulators and Surge Arresters. 2021, (04) Core

Reducing Step Voltages of Grounding Grid in a Substation Considering Personal SafetyChinese Full Text

LI Xin;ZHU Junpeng;LIU Liping;HU Ting;Power Supply Service Center (Metrology Center) of State Grid Hunan Electric Power Co.,Ltd.;Hunan Province Key Laboratory of Intelligent Electrical Measurement and Application Technology;College of Energy and Electrical Engineering,Hohai University;

Abstract: Proper design of a substation grounding grid is crucial to reduce step voltage and ensure personal safety,so it is necessary to study the grid arrangement of grounding conductor in detail. Equivalent circuit models of transmission lines and the substation grounding grid were built in EMTP to calculate step voltages which takes transient characteristics of the single grounding electrode and high frequency circuit model of the human body into consideration. The best dimension of the central mesh in the grounding grid according to exponential law was calculated byadaptive genetic algorithm（ SGA）,and the effect of unequal space arrangement on reducing step voltage is analyzed. Finally,the minimum number of grounding conductors is discussed on the premise of satisfying the safety standard of human body allowable step voltage. Research results show that: After the transmission line is struck by lightning,a relatively high amplitude transient overvoltage will be generated in the grounding grid near the substation,and the overvoltage waveform shows obvious oscillation attenuation. When the mesh size and conductor arrangement are optimized by SGA,the voltage sharing effect is obvious,and the step voltage of the grounding grid can be effectively reduced; The minimum number of earth conductors needed for the layout of earth grid which meets the allowable step voltage limit of human body shows a tendency of decreasing first and then increasing with the increase of soil resistivity.

Keywords：

adaptive genetic algorithm; grounding grid; lighting; step voltage; personal safety; EMTP;

DOI：
10.16188/j.isa.1003-8337.2021.04.006
Series：
(C) Architecture/ Energy/ Traffic/ Electromechanics, etc
Subject：
Electric Power Industry
Classification Code：
TM862;TM63

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Reducing Step Voltages of Grounding Grid in a Substation Considering Personal SafetyChinese Full Text

LI Xin;ZHU Junpeng;LIU Liping;HU Ting;Power Supply Service Center (Metrology Center) of State Grid Hunan Electric Power Co.,Ltd.;Hunan Province Key Laboratory of Intelligent Electrical Measurement and Application Technology;College of Energy and Electrical Engineering,Hohai University;

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