Research Of Fault Location Based On Single Terminal Electrical Data

High voltage transmission line is an important part of power system,the safe and reliable operation of transmission line is very important.When faults occur on the high voltage transmission line,we should locate the fault location accurately and timely for maintenance crew to arrive at the scene and repair the fault section as soon as possible.Fault location can be divided into two types according to the use of electric data quantity.The method using double terminal electrical data is affected less by transition resistance and load disturbance but needs more complex hardware and more invest,furthermore nonsynchronous sampling need to be solved.Fault location using single terminal electrical data needs less hardware but is strongly effect by transmission resistance.This paper gives out a new solution for single-ended line fault location.The fundamental principle is that there exists phase difference between the pre-fault voltage and initial voltage after fault.They have opposite phase at the fault point.By measuring the voltage and current before fault and after fault,the pre-fault voltage and initial voltage after fault in the line can be obtained.This method is clear and easy to implement.But this method has a disadvantage of reaction for transition resistance and results in big error.So this paper presents the positive sequence iterative method to eliminate the transition resistance influence.By calculating the impedance of near system using the negative sequence network and positive sequence impedance of opposite side using near system electrical data.This improvement makes the fault location using signal terminal electrical data have self-adapting to the system's method of operation and increase the precision.The simulation results show the both fault location effectiveness,the combination of the two can meet the engineering practice requirements completely.