Research On Modeling Analysis And Identification Method Of Induction Lightning In Distribution Network

With the constant and complex changes in the current world situation and the rapid and healthy development of China's national economy,power security as a dominant industry is more important than ever.The replacement of insulated bare conductors with overhead bare conductors has reduced the impact of traditional bare conductors on the surrounding environment to a certain extent,and reduced the floor space,but greatly increased the distribution network disconnection failure caused by lightning.The wire breakage faults that occur on the 10 kV distribution network overhead line are mostly caused by line overvoltage caused by induction lightning,and a small part have been caused by direct lightning.A large number of papers analyze the fault characteristics of three-phase lines and the detection and location of the broken lines after the break,but the complexity of the distribution network and the unclear characteristics of the broken faults make the detection of broken lines very difficult.Few people think about it in reverse and analyze it from the root of the disconnection.This paper first analyzes the complex physical process from the start of a lightning strike to the breakage of overhead conductors,details the process of power frequency freewheeling,analyzes the impact of arcs on insulated conductors,and conducts several methods for lightning protection methods Compare and analyze the problems in the current lightning protection.Then the formation of lightning and the formation process of induced lightning and direct lightning are explained.Several models of induction lightning return channel are analyzed and the characteristics of various models are compared.Determine the base current model and return channel model of the paper.Then use Maxwell's equations to derive the calculation formulas of the horizontal electric field component,vertical field component and magnetic field component at any point around the return channel.Then compare and analyze several commonly used field-line coupling models,compare their advantages and disadvantages,and then use the finite time difference method(FDTD)to solve the selected Agrawal field-line coupling model.The influence of horizontal distance and other factors on the induced lightning overvoltage.In the online operation of MATLAB and PSCAD,MATLAB is used to calculate the scattered voltage to be injected on each phase wire,and the wires corresponding to PSCAD simulation are injected respectively,and the induced lightning overvoltage is detected at each detection point of the overhead line.Analyze the induced lightning overvoltage characteristics of different detection points under different horizontal distances and different arrangements of overhead lines.Then detect the direct lightning overvoltage under the same conditions,compare and analyze the difference between the induced lightning overvoltage and the direct lightning overvoltage,and distinguish the two types of lightning on the waveform.