| 35kV is an important class of power system of Dexing copper. But most of transmission lines through the mountainous area with complex landform, strong lightning activity and high soil resistivity. Lightning is one of the main factors affecting the line of power grid stable operation, damaging the production and living facilities when thunderstorm season come every year.According to the lightning protection operation data of 35kV Dashan-Xiashan line, this paper built transmission line of lightning simulation models, considering factors of landform of transmission line aisle, spanning instance and ground resistance, etc. Based on that model, it has made a lot of calculations about the factors of improving lightning withstand level, limiting lightning invasion wave after the line is equipped with MOA.The EGM is more realistic than the standard method because it relates the lightning discharging characteristic with structural dimension of transmission line together. To explain the high rate of lightning shielding failure on the actual operation of lines, this paper calculated the shielding failure rate of "easily struck tower" of 35kV Dashan-Xiashan line with EGM, and the calculation provide a theoretical basis for lightning prevention.According to the study, the main reasons for the high rate of 35kV Dashan-Xiashan line's lightning trip are analyzed, engineering practical measures are proposed to reduce the rate through installing line MOA on the easily struck towers, decreasing tower grounding resistance and installing the negative angle protective pins on the towers of high rate of lightning shielding failure. Practice proves that these measures have good effect on the lightning protection of transmission lines. |
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