The Study On Induced Currents And Induced Voltage Of Multi-circuit Transmission Lines On Same Tower

Multi-circuit transmission on same tower technology can not only reduce the total costand line corridor demand but also improve transmission capacity per unit line and meet thedemand for power transmission. Because of its obviously economic and social benefits, it iswidely used at home and abroad. However, among multi-circuit transmission line on sametower, when one or a few circuits power failure and maintenance and meanwhile the otherlines return to normal operating, the induced voltage and induced current would be producedon the line outage. Especially for high voltage multi-circuit transmission lines on same tower,the induced current and induced voltage can be very high. The study on induced currents andvoltage of multi-circuit transmission lines on same tower contributes much to the advancingof multi-circuit transmission tower technology and the choosing of the grounding switch.In this paper, first of all, a simple theoretical calculation and analysis of induced currentsand induced voltage of multi-circuit transmission lines on same tower was carried out. Thentaking section of multi-circuit220kV transmission lines on same tower of Yao GangSubstation Project for example, a model of multi-circuit transmission lines on same tower wasbuilt in the ATPDraw process, and by which simulation and calculation on induced currentand induced voltage of multi-circuit transmission lines on same tower was calculated in avariety of system operating mode. And then, the influence factors of induced current andinduced voltage of multi-circuit transmission lines on same tower such as transmission linelength, span length, power of transmission lines, soil resistivity and so on were also simulatedand analysed. The general rule of induced current and induced voltage of multi-circuittransmission lines on same tower was obtained. Finally, according to the selection criteriaabout grounding switch in GB, grounding switch for four-circuit transmission line in the sametower in the substation on building are selected, and some recommendations about groundingswitches selection are provided.