Research on interference characteristics of secondary cables due to lightning stroke in grounding grid of substation

The lightning current might inject grounding grid through the grounding lead when the arrester suffered a lightning wave in substation. Then the ground potential difference(the difference of ground potential can/may) generated interference voltage on secondary cables due to earth potential rising. The interference voltage might lead secondary equipments misoperation and even damage. To analysis the problems mentioned above, a equivalent circuit model was established. The transient voltage caused by ground potential difference to secondary cables could be (can be or is) calculated by EMTP-ATP. As a validation, the impulse voltage generator was used as voltage source to simulate that substation encountered with the lightning, and to measure the interference voltage at cable terminal as well. Both experiment and computer simulation had been taken to analysis the influencing factors of the interference voltage on secondary cables and the ports of secondary equipments. The factors included the lightning current injection point and the soil resistivity rate. The analysis would provide a reasonable reference for wiring cables to improve anti-jamming capability of secondary equipments in substation.