Research On Application Of Fault Location Technique For Distribution Network Using The Information Of Fault Indicator And PMU Measurement Devices

In China,non-effectively grounding modes are widely adopted in power distribution networks.After a single-phase-to-earth fault occurs,the distribution system can still operate for a period of time since the fault currents are small.Although the reliability of power supply can be ensured,it brings some difficulties to the fault location.In recent years,the researchers at home and abroad have been dedicated to exploring the methods of fault location for distribution grids.Due to the complex structure,many branches and integration of distributed generation,the problem of locating faults in distribution networks has remained unsolved,which hinders the development of intelligent distribution networks.Thus,it is of great significance to studying a practical and reliable fault location method for modern distribution networks.Considering the intelligent measurement devices,new or existing,such as fault indicators and phasor measurement units,the steady-and transient-state characteristics of zero-sequence components after a fault occurs in distribution networks are analyzed in this paper.The current flow of zero-sequence components and action states of the fault indicators are explored.By sectioning the distribution network,the criteria for fault section detection is proposed considering the topology of networks.In order to achieve accurate fault location,based on the lump parameter model and minimum fault reactance concept,the accurate fault location formula using the phasors measured at main station and buses of distributed generations is presented according to the thevenin equivalents.IEEE-34 bus simulation test system is constructed in PSCAD/EMTDC to verify the proposed fault location method.Various fault conditions,penetration levels of distributed generations,and load variations are considered.The method is carried out in MATLAB and the results demonstrate the effectiveness,accuracy and reliability of the method.A software system of fault location for distribution grids is designed in Labview platform.The simulation data is utilized to test the performance of the established system.The results indicate that the constructed system has high practical value and interactivity.