Study on the combination measures of the lightning back-striking protection for 110 kV six-circuit transmission lines on the same tower

Because it is vulnerable to lightning for 110 kV six-circuit transmission lines on the same tower (SCTLST) and the existing lightning protection measures are not effective in reducing the back flashover trip-out rate, new measures to improve the back-stroking lightning withstanding level of transmission lines are researched. Firstly, based on the calculation method of critical parameters that characterize the back-stroking lightning withstanding level of transmission lines, the back-stroking lightning withstanding level simulation model of 110 kV SCTLST is established. Then, different modes, namely no lightning protection, installing coupling ground wires and lightning arresters, installing both coupling ground wires and lighting arresters, were respectively simulated and analyzed. The results showed that, considering the cost of maintenance and economic, the combination measures of the lightning back-striking protection-equipped with lightning arresters on the top and coupling ground wire can greatly improve the back-stroking lightning withstanding level and reduce the back flashover trip-out rate. It is significant for lightning protection engineering design of multi-circuit transmission lines on the same tower.