A simulation model of polluted insulator string with local arc based on ATPDraw is proposed in this paper.The parameter of arc is set based on nonlinear curve shape and the data of arc characteristics.The pollution resistance of different stypes and pollution degrees is estimated based on shape factor and pollution conductivity.The arc phenomenon of light and heavy pollution can be simulated by the model,the interaction of every insulator is reflected by the voltage of every insulator,and the transient travelling-wave can be acquired by high frequency sampling.

This article introduced single terminal principle and mathematics morphology,and proposed a method to analyze the fault transient signals with mathematical morphological grads.This method separates forward and reverse traveling wave by mathematical morphological grads transform,which can not only detect the moment of signal mutation in transient traveling wave,but also have certain capability of interference rejection.Simulations with PSCAD show that this method is feasible,reliable and accurate.

This paper analyses the Rogowski coil for measuring principle and establishs a transfer function model.The paper makes in-depth study about the relationship between Rogowski coil parameters and the characteristic of high frequency transition.The results show that the cut-off frequency of the Rogowski coil can reach hundreds MHz if reducing the resistance and distributed capacitance while keeping a certain self-inductance certain as possible as.Rogowski coils can meet bandwidth requirements of high-frequency traveling wave signal and can measure the traveling wave.