Research Based On The MODELS Language Of Calculation And Protection Of Lightning-induced Overvoltage Of Distribution Network

The most part of the distribution lines are exposed in the air, so they are apt to bedamaged by lightning over-voltage,which will interrupt power supply and affectuses’ production and lives.Research indicate that the main factor of distribution lines’insulator flashover,and the proportion of accidents by induced lightning exceed90%.Therefore, It’s significant to research the calculation prevention of lightning inducedovervoltage on distribution lines.Firstly,a detailed description of the physical mechanism of lightning discharge isintroduced,several calculation models about return-stroke current are compared andanalyzed,and introduced the various models of characteristics,and determined theMTLE model in this paper.Secondly,establish the mathematical model of the electromagnetic field near thelightning channel, reference Maxwell equations, applicat dipole theory to derivatespace radiation field produced by a current dollars, the expression of lightningelectromagnetic pulse field at any point in space has been getted. WithCooray-Rubinstein formula deduce electromagnetic field surrounding the lightningchannel considering the earth conductivity. Using Agrawal field lines coupling modelas the coupling model of the line and transmission line has been determined and usedifference formula to show the derivative of electromagnetic field induction lightningovervoltage with lightning overvoltage of overhead distribution lines is obtained byusing the finite difference time domain method.Then,a model supports file is create,which defines input and output.TheMODELS language is used to simulated induced over-voltage module,and thetransmission line is simulated by the Bergeron classic model.In addition,the lightningvoltages on distribution characters were analyzed.Researched the teturn strokevelocity,different high of overhead line and the lightning current amplitude factors which affect the lightning induced voltage.Finally, this paper analyses the distribution line lightning flashover fault andmakes a discussion of the design of the parameters and the calculation of distributionlines lightning trip based on ATP-EMTP simulation. An example of Tianjin DaGangOilfield distribution lines is taken, which focuses on the density of mounting the linearrester distribution lines to reduce the effect of induced over voltage,the last，thelightning protection measures are given for the Guanzao line311which the effect oflightning protection is evaluated.