Research On Fault Location Of Transmission Line Based On Wavelet Analysise

In recent years,the research of smart grid in China has made remarkable achievements,followed by the increasing power grid capacity and transmission distance.As the way and link of energy transmission in power system,transmission line is responsible for the connection between power generation end and power consumption end in power system,and it is particularly important to ensure its normal and stable operation.Therefore,in this paper,the transmission line protection and fault phase selection and location problems are deeply analyzed and studied.Firstly,a transmission line protection method based on wavelet transform and neural network is proposed.The phase current is transformed by Clarke transform to get the corresponding modulus component,and then the modulus maximum of the signal is obtained by wavelet transform and input to the neural network,and the operation state of the transmission line is judged by analyzing the output value of the neural network.The simulation results show that the proposed method can meet the requirements of transmission line protection,and is not affected by external conditions.Secondly,a fault phase selection algorithm is proposed based on wavelet transform and the characteristics of boundary conditions when different types of faults occur.By studying the basic principle of fault phase selection of transmission line,the criterion factor and phase selection discriminant are determined according to the difference of fault characteristics under different fault types,and the proposed fault phase selection algorithm is verified according to the phase selection discriminant.The results show that the analysis of phase selection criterion is accurate,and the fault phase and non fault phase can be correctly distinguished,and the phase selection result is not affected by the change of external factors.Finally,a fault location method of transmission lines is proposed.The db4 wavelet is used to transform the mode component of the phase voltage,and the fault location is realized by combining the theory of double-ended traveling wave location.The simulation results show that the proposed algorithm can achieve transmission line fault location well,and has good stability,and can still accurately locate the fault position when the conditions such as fault location change.