Research On Fault Location Of Power System Of Submarine Observation Network Based On Traveling Wave Time Difference

As the world's third largest observation platform,the Seabed Observation Network plays a key role in marine environment observation and disaster prediction.Due to the special deep-sea environment in which the seabed observation network is located,the current fault location method for its power supply system mostly uses the impedance method.Due to the influence of seawater temperature and transition resistance,the positioning accuracy cannot meet the engineering requirements.Therefore,how to extract the transient characteristics of submarine cable faults and use transient components to solve the problem of submarine cable fault location accuracy has become the key to the current subsea observation network power supply system fault location problems.The thesis focuses on the problem of fault location of traveling wave in the power supply system of the submarine observation network,and conducts theoretical research on the detection method of submarine cable fault traveling wave and the fault location of submarine cable based on traveling wave time difference.In order to achieve the purpose of improving the accuracy,accuracy,reliability and reducing errors of submarine cable fault location.The power supply mode and system framework of submarine observation network are analyzed,and the power supply model of submarine observation network of negative high voltage single pole DC transmission is established.The distributed model of submarine cable is analyzed and the transmission law of traveling wave in submarine cable is clarified.Then the types and causes of submarine cable fault are summarized.An improved fast independent component fault traveling wave detection method is proposed.Fast independent component analysis can accurately separate the independent signals from the mixed signals,and extract the characteristic components one by one.This paper analyzes the fast independent component analysis method based on negative entropy and kurtosis,and optimizes the step size and kurtosis of the fast independent component analysis method based on kurtosis to ensure the accuracy of traveling wave detection.The simulation results show that the fast independent component method based on kurtosis can accurately separate the traveling wave signal in the fault environment with large interference noise,reduce the interference of noise to the fault traveling wave,and has good anti-interference performance.A fault location method of submarine cable based on multi terminal traveling wave time difference is proposed.After the failure of submarine cable,the fault line is determined by intelligent branch unit,and the shortest transmission path of the initial traveling wave head is determined by Floyd algorithm.Then,set the sub-cable equidistance points,establish the traveling wave initial path matrix from the sub-cable end points to the equidistance points,and then establish a database of traveling wave wave head arrival time before failure.After the fault occurs,the arrival time difference matrix of the fault traveling wave head is constructed by using the time of the fault initial traveling wave head captured by the traveling wave acquisition device.Finally,the time difference matrix after the fault is compared with the time difference matrix in the database to determine the fault location.Through PSCAD simulation analysis,it is found that this method can accurately locate the fault location,with good accuracy,high fault tolerance rate and simple implementation.It can become the basic guarantee for the stable operation of the power system of the undersea observation network.The thesis introduces the traveling wave method into the fault location of the submarine observation network power supply system,which can realize the accurate positioning of the observation network power supply system,make up for the problem of low steady-state feature positioning accuracy,facilitate the later maintenance and protection work,and have certain practical engineering significance.