Study On Distribution Lines Lightning Protection Scheme Evaluation System Based On Improved Lightning Trip-out Rate Calculation

Distribution lines need to be differentiated against lightning according to line parameters and actual engineering factors due to it's low insulation levels and wide distribution.The accurate calculation of the lightning trip-out rate is the basis for accurately assessing the lightning performance of the line.The establishment of the lightning protection evaluation system is the key to differentiate lightning protection,and the actual lightning data cannot be ignored in the lightning protection of the distribution lines.Therefore,the accurate calculation of lightning trip-out rate and the comprehensive lightning protection scheme evaluation system have important engineering application value and scientific significance.Firstly,the paper analyzes the line structure and parameters of the 10 kV distribution line in Guangdong Province,and established an accurate lightning overvoltage simulation analysis model based on the PSCAD/EMTDC.Secondly,the lightning data of the line from 2015 to 2018 are statistically analyzed and the cumulative probability distribution of lightning current magnitude is fitted.The lightning strike ground and the critical distance of the lightning strike are detected according to the calculation method of the hitting distance.The improved calculation method of lightning trip-out rate of distribution lines is proposed according to the idea of calculating the probability distribution curve of different induced overvoltage amplitudes proposed by JG Anderson and the statistical probability by the Monte Carlo method.Then,the effects of grounding resistance and line arrester on the transmission characteristics of lightning current on the tower and the conductor and the shunt characteristics of the tower are studied.The lightning withstand level of the line under different arrester configuration schemes is calculated.The differentiate lightning protection scheme has carried out economic and technical comparisons.And the universal lightning protection scheme for distribution lines has been proposed with the goal of reducing the lightning trip-out rate.Finally,six typical distribution line lightning protection schemes were selected with lightning trip-out rate and anti-breaking effect and so on as the target,and the weight coefficients of the scheme were calculated based on AHP,the distribution lines lightning protection scheme evaluation system were established based on MATLAB GUI.