Fault Location Technology In Electrical Distribution System

Neutral point in Medium Voltage(MV)distribution networks are usually unearthed or compensated,also known as neutral point non-effective grounded networks.For these networks,it is difficult task to locate a fault location because the network can run under fault condition for a short period of time.Normally fault location detection method in medium voltage distribution network(MVDN)is detected through different grounding methods,different solutions using arc-suppressing coils grounding is created after permanent single-phase ground faults occur.This paper presents a traveling wave signals detection method for detection of fault location.After the fault occurs anywhere at the distribution network,a travelling wave(TW)will be generated at fault point that can propagated as step wave in both directions.In this paper first disturbed surge of that TW is used for fault location detection with precise timing on both multi terminal measurements.The method of determining the fault location using precise measurement of the first surge of TW arrival time at both ends of the distribution line.At fault point,TW is reflected and refracted to both the directions and amplitude of the reflected current traveling wave is large and the characteristics are obvious.Fault section detection in MV distribution lines are detected through the time precision of first reflected surge at the bus bar.As we know Potential transformer(PT)¤t transformer(CT)produce some oscillation in the power lines so there are complex surges on the bus bar so we can’t identify the multiple surges for time precision.Only first disturbed reflected surge is useful for fault section detection and time precision for distance calculation.Smart meters are installed on the bus bar in substation that can measure the TW reflected time using BeiDou time synchronization network.Smart meter also measure the reflected current wave surges from different feeders line and calculate the distance between faulty points to smart meter.The transmission characteristics of the current TW on the line and multi-ended ranging strategy using the traveling mode zero-mode component and the line mode component for fault location are analyzed for distance calculation.Depends on the characteristics of distribution network,this thesis also studies the solution of overhead line,cable hybrid line and the integrated ranging technology that uses the information of multiple detection devices.The simulation results of ATP/EMTP software prove the accuracy and practicability of the proposed fault location method.