A travelling wave fault location combined method based on fault characteristic frequency band

When fault occurred in power grid, the fault location method based on aerial mode velocity and zero mode velocity of travelling wave will reduce the accuracy of location, because that the zero mode velocity vary with the variance of frequency. To solve this problem, a combined method for fault location based on fault characteristic frequency is proposed in this paper. Firstly, the method analyzes the frequency characteristic of zero mode and aerial mode velocity. Secondly, it calculates the similarity index of initial wave and reflect wave under each frequency band. And then choose the frequency band with biggest similarity index as the characteristic frequency band. Then calculate the zero mode velocity in the band to do the fault location preliminary and correct the fault location using aerial model velocity finally. PSCAD/EMTDC simulation is built under different fault conditions. And the result illustrates the accuracy and reliability of the method.