A Method for Eliminating the Aperiodic Component of Fault Current Based on Three Sampling Values

When a near end short circuit occurs in the contact network, the feeder current contains large and long-lasting aperiodic component, which may affect the sensitivity of feeder distance protection and the accuracy of fault location. This paper presents an improved Fourier algorithm based on the exponential decay characteristics of aperiodic component, which utilizes three data points within one cycle after a fault to reduce the impact of aperiodic component. Through the analysis of simulation data and on-site measured fault waveform data, it has been verified that the proposed method can effectively reduce the errors in current and reactance calculation, thereby improving the sensitivity of relay protection and reducing the errors in fault location.