Study To Lightning Protection Performance Of 110kV Transmission Line In YIBIN

Lighting stroke is the main reason of transmission line faults, 110kV overhead transmission line play a important role in the power system.So simulating and calculating the lighting proof performance of 110kV transmission line has significant instructions in the insulation design of transmission lines. It is necessary to prevent the transmission line faults and improve the lightning-withstand level though simulating and calculating the lighting proof performance of 110kV overhead transmission line.The back stroke performance of 110kV overhead Transmission line is calculated in this paper using rule method and ATP-EMTP simulation and the distributed parameter model of tower is built , It can truly reflect the spreading course of lightning current on the tower. The results indicate that, the simulation results is a little higher than the calculation results by rule method and the lighting current withstand level of back stroke increase with the decrease of the tower surge ground resistance, the decrease of the tower height and the enhancement of insulation level.The shielding failure trip rate is calculated based on the Electrogeometric model in this paper. The results indicate that the shielding failure trip rate decreases with the decrease of the shielding angle, the decrease of the tower height and the enhancement insulation level. Especially, the shielding failure trip rate increases more rapidly, for the towers which located at deep gradient or windy zones.The results indicate that the lightning-withstand level can be improved through the follows:1) For the tower Z1: the height of the tower don't exceeds 13.9m,the shielding angel should be below 25°and the ground resistance should be less than 10 ohm; when the ground gradient exceeds 35°, the shielding angel should be less than 20°.2) For the tower Z3: the height of the tower don't exceeds11m,the shielding angel should be below 17°and the ground resistance should be less than 10 ohm; when the ground gradient exceeds 35°, the shielding angel should be less than 15°.3) For the tower110ZGU₂: the height of the tower don't exceeds 16m,the shielding angel should be below 17°and the ground resistance should be less than 4 ohm; when the ground gradient exceeds 35°, the number of insulators should be 9.