Study On Calculation Of Shielding Failure Flashover Rate For Transmission Line Based On Electric Geometry Model

At present,the main methods to evaluate the characteristic of shielding failure for transmission line are the standard method, LPM and EGM.The EGM relates the lightning discharging characteristic with structural dimension of transmission line together.From lightning and lightning conductors on the pilot line sensors charge of of difference the electric field, the text establishs the vector EGM based on the electric field around change the lightning leader selective. And calculates shielding failure rate using around the arc-projection distance-based, comparing with classic EGM calculation method. The results showes that: In this paper, the vector EGM reveals the electrical transmission lines from lightning strikes the deep-level mechanism to explain the actual lines running around the shielding failure rate too large and the large current around-the cause of the accident, for the rate of transmission lines lightning trip-out and the calculation of the level of tolerance lightning and lightning accident prevention and analysis provides a theoretical basis.Then to the vector EGM as a criterion blow around, electromagnetic transient procedures ATP-EMTP and Monte Carlo method, the text establishs a new model of calculating shielding failure trip-out rate. And using the model calclulates shielding failure trip-out rate of one 500kV transmission lines, the point of order method comparison of the results. The results show that the model presente in this paper than the order of transmission lines around better reflect the actual situation of trip-out.The influence of many aspects to shielding failure trip-out rate is discussed. Some measures are suggested to reduce shielding failure of transmission line.The text makes further study for striking distance.