Study on the Calculation Method of Interference Voltage of Shielded Cable under the Condition of Lightning Strike in Smart Substation Grounding Grid

[摘要] When lightning strikes the substation grounding grid, there will be a great transient ground potential difference between the two grounding points of the shielded cable with two terminal grounding. It will be coupled to the cable core line and affects the normal operation of second order system devices and even jeopardize the safe operation of the whole system. Therefore, it is of great significance to study the lightning characteristics of the relevant components when lightning strikes the grounding grid of smart substations. This paper mainly studies the calculation method of interference voltage generated by shielding cables when lightning strikes the grounding grid of smart substations. Firstly the equivalent circuit and the multi-conductor transmission model of the cable are established. Then, using the frequency domain method in the multi-conductor transmission line and combining the fast Fourier transform technique, the steps of calculating the interference voltage and current produced in the two cable are given. Finally, in order to test the validity of the proposed calculation method, the lightning impulse grounding test is carried out on the test grounding network. The test results show that the method is effective.

[发布机构] School of Electrical and Electronic Engineering, Wuhan Polytechnic University, Wuhan; 430023, China^1;Huaneng Wuhan Power Generation Co., Ltd., Wuhan; 430015, China^2

[效力级别] 无线电电子学

[关键词] Frequency-domain methods;Ground potential difference;Lightning characteristics;Multi-conductor transmission lines;Relevant components;Second-order systemss;Substation grounding;Transmission model