Practical improvement of frequency-domain-based two-terminal fault location software

The frequency-domain-based two-terminal fault location is often influenced by the format difference of fault recording data,the transient distortion after fault and the robustness of algorithm itself,which may cause failure or great error.Based on the source of these errors and the characteristics of fault recording data,a set of practical procedures and measures are researched,including fault recording data pre-processing,transmission line model and improved fault location algorithm.The main differences between the configuration file and data file of COMMTRADE data format are summarized in sample data index,phase identity and bit number of digital data.The algorithm is proposed to adaptively intercept the data window for FFT calculation using the detection of fault start and end times with the recording data,which lowers the influence of the transient distortion after fault.The pre-fault constraints are used to synchronize the recording data of two terminals.The lumped parameter modification model and indistinct region method are proposed to improve the fault location accuracy.The practicability and validity of the improvements are verified by the result of a typical practical fault location in Guangdong power grid.