Research And Application Of Differential Lightning Protection Technology For Transmission Lines

In the past 20 years,with the rapid development of China's national economy,great progress has been made in power grid construction.Due to the significant increase of severe convective weather,the frequency of lightning fault is significantly higher than before,and it shows a series of new features different from the traditional fault.The single-phase grounding,two-phase flashover and other problems caused by lightning stroke are increasing.The lightning protection work of transmission lines is proposed There are many new challenges.Due to the influence of lightning weather,the transmission line will have the problem of lightning trip in the normal operation process.Therefore,China's power groups and government departments pay more attention to the problem of transmission lines suffering from lightning stroke.It is necessary to further carry out the research and application of differential lightning protection technology measures for transmission lines,and actively explore reasonable and effective prevention strategies.Based on the formation mechanism of lightning over-voltage of transmission line,this paper discusses and analyzes the lightning protection measures,and puts forward a protection strategy for the electric field distribution of parallel gap of composite insulator of lightning protection line.This strategy can not only filter the noise in a large range,but also create a rigorous and reasonable arc time model,so as to realize the analysis of the movement of parallel gap of arc current.In this paper,according to the arc time model,the electric field intensity of the parallel gap is solved by the finite element method,and the distribution of the electric field in the parallel gap is derived.In view of the risk of lightning damage caused by surrounding lightning in the operation of transmission lines,this paper studies the lightning resistance performance of transmission lines through the electrical geometric model.Aiming at the lightning risk of transmission line in the process of operation,this paper uses ATP-EMTP program to analyze,on the basis of comprehensive consideration of lightning activity state.climate characteristics and other related factors,establishes the lightning risk analysis model of transmission line.At the same time,under the guidance of the improved AHP,an objective and comprehensive evaluation model for lightning protection measures of transmission lines is established.In this paper,the differential lightning protection technology and configuration scheme of transmission lines are analyzed,and the evaluation model of lightningprotection effect is established to evaluate the lightning protection effect.After the official operation of 500 k V zouchuan line,there were four lightning trip faults in total,two in 2013 alone.The probability of lightning trip fault is significantly higher than the current relevant standards.Therefore,this paper takes this line as a typical line for lightning hazard risk analysis,develops a differentiated lightning protection reconstruction scheme,and achieves good engineering application results.