Power Line Fault Localization Based On Multiple Measurement Points

In recent years,the electrical failure has influenced power supply reliability and people’s property and life safety seriously.The fault arc is an important factor to produce electrical fault,which occurs easily in any position in the distribution system such as residential,store,mine,aircraft and automobile.The aging and loose connection of Lines and distribution equipments will cause edm and arc.The RMS of current when Series arc-fault occures often below the normal current.So the existing protection devices will not act.If the fault cannot be removed promptly,it will produce local high temperature which will damage distribution equipments or cause fire accidents.Catastrophe theory is to study the sudden change occurring during the process of continuous development.The running state of the line from the normal operation to arc fault is actually a kind of catastrophe phenomena.Therefore,the catastrophe theory is applicable to the study of arc fault.Thus,this paper puts forward the arc fault detection method based on catastrophe theory.First,in order to further study of the characteristics of arc fault,this paper sets up the experimental platform for fault arc.Then carry out series arc fault Simulation experiment in a variety of different types of loads to collecte a large amount of data.According to the mutation of current waveform when arc-fault occures,Employ Integration,root mean square(RMS)formula,wavelet analysis and Fourier analysis to extract features of current in time domain,time-frequency domain and frequency domain.At this process,four characteristics which are variation coefficient of the integral value,RMS between two adjacent cycles currents,variation coefficient of high-frequency coefficients and high order harmonic component variation are defined to indicate the degree of mutation。Second is establishing the arc fault evaluation model.The research method of evaluation index based on catastrophe theory is adopted to evaluate the mutation characteristics extracted above synthetically to obtain arc fault evaluation index.The result shows that the characteristics and evaluation index of two cycles current before and after arc fault occurred is significantly increased compared to normal operation,Which can effectively distinguish fault arc and differentiate the current when the load starts or changes with good generalization and robustness.Finally,this paper designs the software and hardware of arc fault circuit breaker based on digital signal processor dsPIC30f2010 and mainly completes the detection of current,display of fault,button testing and the circuit breaker tripping.