Research On Traveling Waves Fault Feeder Detection And Fault Location Method For Smart Distribution Power Networks

With the rapid development of smart grid,distribution network links closely to users,its reliability plays an important role in national economy and daily life.Power supply system stability and power quality is directly affected by distribution network faults.Therefore,establishing reliable distribution network fault line selection and location system become an urgent need of developing smart grid.In order to solve problems of fault line selection and accurate location in intelligent distribution network,mature traveling wave fault location for transmission line is effectively applied in distribution network,traveling wave fault line selection and location system for intelligent distribution network is studied in this thesis.Firstly,in distribution network,traveling wave transmission characteristics are researched,impacts of mixed line multi-branch lines and distribution transformer on traveling wave transmission characteristics are analysed.Since the arriving time data of traveling wave front are extremely enormous in complicated distributed networks,The Chauvenet algorithm is proposed and applied to eliminate crude difference of arriving time data.According to distribution network topology structure and mixed lines,the first and end time characteristic matrixs of each line are established;fault time matrix is built using the accurate first-traveling wave arriving times to every station and the end of each branch line.The first and end line time characteristic matrixs and fault time matrixes are matched by using least square method to eliminate interference and accurately search the fault line.On the basis of fault line selection and different structure of the distribution network,precise fault position will be calculated through graph theory method and least square method.A complete set of distribution network fault line selection and location device based on traveling wave is designed.All the research on this thesis will lay the foundation for distribution network intelligence.The system can realize distribution network fault line selection and location.What's more,its mixed line adaptive reclosing schemes can ensure:reclosing signal will be shielded when the fault occurs in the cable,or will be opened.Traveling wave fault location and adaptive reclose for mixed line,are not affected by fault location,fault types and transition resistance,reduce the fault time and improve the reliability of distribution network.All the research on this thesis will lay the foundation for distribution network intelligence,and meet the requirement of high reliability and real-time for smart grid.