Methods To Measure The Fault Distance Of Mix Circuit Sconstituted Of Electric Cable And Stilts Research

Fault location of hybrid transmission line is a problem that is concerned a lot. Traveling wave fault location method for the hybrid transmission line has already been widely used in power system currently. But there are some issues on the realization of this method: accurate extraction of transient traveling wave component in the transmission lines, distinguish and calibration of the reflected waves of the faulted point and wave velocity determination. These problems have seriously affected the precision of fault location in hybrid transmission line. Therefore, how to improve and perfect the traveling wave fault location method becomes an important subject which people have to face with.After the study of existing methods of traveling wave fault location, a double-ended fault location method of single-spaced wave velocity is proposed in this paper.Firstly, the paper presents a discriminant method of fault section in cable-overhead hybrid line. The method is based on the derivated negative network of the hybrid transmission line, and derives out negative distribution current at both ends of equipment network in the connection point of cable-overhead hybrid line in the hybrid transmission line, and then uses the mode value of these two current to compose of the size of the comparison criterion in order to achieve fault section determination when the right place A single-phase ground fault occurs in hybrid transmission line.Secondly, through the discussion of the theory of wavelet analysis of line process analysis in the transmission lines on the road traveling wave fault, the use of B-spline wavelet on the line fault current traveling waves in multi-scale wavelet decomposition to determine the time of the traveling wave fault location . Thirdly, the single-spaced wave velocity algorithm is given to solve the problem of transmission velocity discrete of the mixed lines, and achieve two-terminal traveling wave fault location of the fault line.Finally, several simulation examples are done. And results show that accuracy and feasibility of the method is proposed in this paper.