Research On Online Fault Location Technology Of 10kV Single Ring Cable Feeder Based On Traveling Wave Principle

With the reconstruction of urban power networks, cable lines have been widely used in distribution networks. It is an inevitable trend in urban power networks that power supply by cable lines instead of overhead lines. To ensure the reliability of power supply and the quality of electricity, it is imperative to location the cable line fault accurately and quickly. At present there is few study on cable line fault location, analysis on location of the lines with branch and the cable networks is still a new research area.Through the research on traveling wave transmission as well as the refraction and reflection phenomenon, fault location based on double ended traveling wave is analyzed. The cable networks’structure has been divided, and the fault scheme under this division has been put forward. The single ring cable feeder is divided into different levels. The final results can be get after statistical analysis of preliminary data. During data-processing, Grubbs test is utilized to eliminate wrong data.The location theory and arithmetic about T-type line have been devised. By using the theories of cubic Bspline wavelet transform and modulus maxima, the exact arrival time of traveling wave have been acquired, then the initial location data can be calculated; judging the fault section before the finally fault location. If the fault is outside T-type line, the appropriate recording will be keep automatically.Because the volume of data is usually huge, the concise optimized scheme has been proposed. Choosing a part of essential T-type lines by particular principles can ensure the accuracy of result as well as reduce computational effort, less time for location, and can be more practical.In order to verify this design, the single ring cable feeder was simulated by PSCAD, and the data was obtained, program with MATLAB language was worked out. Simulation results showed that the error is 1.21m and elative error is 0.0378% in the 10km lOkV single ring cable feeder. The result also showed that Grubbs test is accurate and reliable, the accuracy of optimized scheme is identical to the original scheme while the time spend is reduced.Finally, the technical problems in single ring cable feeder fault location are described and analyzed.