Research On Distributed Traveling Wave Fault Location Method Based On Non-contact Measurement

The accuracy and reliability of the fault location of the transmission line are related to the safe and reliable operation of the power system.The traveling wave fault location method has higher accuracy than the fault analysis method,but there are still some problems in practical applications.Therefore,further research on traveling wave fault location will help improve the accuracy of fault location and maintain the safe and stable operation of the power system.This paper proposes a non-contact traveling wave fault location method,which can collect three-phase composite traveling waves according to the spatial electromagnetic field under the transmission line;analyzes the aliasing phenomenon of modulus maximum points in wavelet transform and proposes solutions;combined with distribution It proposes a distributed traveling wave fault location method based on non-contact measurement,and analyzes and solves the fault situation of the railway through-line mixed with overhead lines and cables.The main work of this paper is as follows:(1)Research on distributed traveling wave fault location based on non-contact measurementThis paper studies the non-contact traveling wave measurement method and the distributed measurement method based on space electromagnetic field acquisition,and combines the two to propose a distributed traveling wave fault location method based on non-contact measurement,and distributed non-contact traveling wave measurement devices.Collect the three-phase composite fault traveling wave to obtain the arrival time of the traveling wave;after determining the fault section,dynamically obtain the fault section wave speed according to the principle of distributed measurement,and finally use the double-end ranging method to determine the location of the fault point.It has been verified by simulation that this ranging method has high ranging accuracy,good reliability,and strong security.It has good applicability to various line conditions and avoids the complicated installation of devices in conventional distributed traveling wave fault location.Maintenance process.(2)Research on the aliasing of wavelet transform modulus maximum pointsTravelling wave signal has many nearby abrupt points or improper selection of wavelet base will cause the aliasing phenomenon of wavelet transform modulus maximum point,resulting in poor adaptability of wavelet transform.This paper proposes a method for judging the modulus maximum point based on the monotonicity of the signal after the mutation point and the position of the peak and trough of the wavelet transform.After simulation verification,this modulus maximum point aliasing processing method can effectively improve the applicability of the wavelet transform.Reduce the error of traveling wave fault location.(3)Research on non-contact distributed traveling wave fault location of railway through lineThe unique electrical characteristics of railway through lines make it impossible to directly apply conventional traveling wave fault location methods.Therefore,this paper proposes an equivalent conversion method to process railway through lines with a mixture of overhead lines and cables,and convert the mixed lines into overhead lines in a unified manner.Then,the distributed traveling wave fault location method based on non-contact traveling wave measurement is used to locate the fault.The modeling simulation and comparative analysis of actual 10 kV railway through-line faults verify that this method has high ranging accuracy and has certain advantages compared with traditional traveling wave fault location methods.