Cable Fault Location Based On The Pulse Injection Method

Because of the increasing of operation load and time of power cables, and theapplication of power cables is more and more gradually, the rate of cable fault in powersystem is higher and higher. So it is one of the main obstacles to the normal power supplyof power supply department now. But, until now, there are no efficient methods withwide applicability and strong practicality on power cable fault location. Through researchon existing power cable fault location technology, this paper makes a comparativeanalysis of main location methods, point out the merits and defects of each method. Amethod of cable fault location based on pulse injection method has been promoted inthis paper after study to the method of traveling wave. After injecting high voltagepulse into the fault phase of power cable, the fault point will discharge and thevoltage wave will form a sudden jump. Signal receiving circuit can receive thesudden jump of returned voltage wave at the pulse injection end. The fault point canbe calculated based on the time difference between pulse injecting and receiving.The devices are simple and easy to be operated, and the effect is stable. The designof high voltage pulse generator is essential to effective localization in this method.This paper puts forward the design of high voltage pulse generator. The width andperiod of injected pulse are adjustable, and it can detect various types of cable faults,furthermore, it can be used in various methods and principles of fault pre-locationand precise location. This paper furnishes the general scheme of cable fault locationsystem, and explains the hardware and software design of high voltage pulsegenerator and signal receiving circuit in detail. Through theoretical analysis andlaboratory cable discharge simulation experiments, the feasibility of the design of highvoltage pulse generator is proved, and it also illustrates the application of pulseinjection method in cable fault location is feasible.