The Study On Traveling Wave Fault Location And Analysis Of Fault Transient Signal In Transmission Line

When faults occur on the HV transmission lines, fault signals contain all kinds of fault information. Extracting characteristics information effectively of fault signals will serve the power system protection, or fault diagnosis. When faults occur on transmission lines, accurately and timely locating the fault position can rapidly eliminate the fault and resume the power supply. It is of great importance to ensure a proper operation of the system.This paper analyses the fault Electromagnetic transient state of transmission lines and simulation results show the spectra characteristic of fault transient current in the frequency-dependent parameter model, distributed parameter model andΠtype equivalent circuit model. Also, the frequency and length of relationship curves under distributed parameter model andΠtype equivalent circuit model is given.According to the theory of the refraction and reflection of traveling wave, the paper analyses the transmission process of fault traveling wave with the help of the grid way. Using PSCAD/EMTDC, two simulation models are designed based on one, both ends of bus with only a fault line, and another, both ends of bus with three outgoing lines. In both simulation models, amplitude relationship and polarity relationship between reflected wave of bus-reflection and reflected wave of fault point are analyzed. Based on the polarity relationship result, the method of wavelet transform modulus maximum and the approach of multi-resolution morphology gradient are used separately to detect traveling wave front arrival, and obtain precise polarity of traveling wave, and then single ended fault location using transient current traveling waves has been realized. According to the model of practical power system transmission lines, simulation results show that the fault location methods are availability and accurate.An adaptive algorithm is introduced to meet demands of traveling wave arrival time's extraction in the white noise environment. The method can effectively remove modulus maximum value of noise and retain the traveling wave modulus maximum value information. Results of theory analysis and power system transmission lines simulations show this method is effective. In consideration of the short comings of wavelet transform in eliminating pulsed noises, the morphological filtering of mathematical morphology is used to filter random and pulsed noises contained in fault transient signals.