Study Of Faulted Cable Fault Location Method Based On DSP Technology

Power cable is applied in power system extensivly. Probability taking place in cable fault is greatly increased along with run-time, as many factors, such as power insulation aging and machinery damage. On-line fault location technologies are urgent need in power cable systems.In this paper, on-line fault location method and new technologies are analyzed and compared systematically. Several important and difficult problems should be thought of carefully about on-line fault location in cable power system, which transformer neutral point not directly grounded. Firstly, what's the characteristic of the traveling wave during its propagation; Secondly, will the fault point characteristic affect the traveling wave; Thirdly, how will the fault information change at the measuring point; And the last but not the least, how to determine accurately the arrival time of the traveling wave.A sample power cable system is created, with a transient simulation tool ATP/EMTP (Alternative Transient Program) based on a 10kV XLPE (Cross-linked Polyethylene) cable model in the paper. Under this model, the characteristic of fault current is simulated in different fault grounding modes. Fault point characteristics are simulated to determine their effect to traveling wave. The break point characteristic of fault traveling wave is found by using wavelet transform and local module maximum method, and judged the question whether or not the fault is happened by the criterion of fault traveling wave singularity. If that's ture, the fault distance is worked out with the improved arithmetic of fault location. Moreover, the factors affecting the on-line location accuracy is discussed, and the means which eliminate the influence also is canvassed.For the usability of testing the thesis and studying, design a data processing system for XLPE cable fault location. The hardware of the system mainly including DSP (Digital Signal Processing) minimal system design, A/D conversion circuit design, power supply module design, the memory module circuit is designed, and the logical control module circuit is...