The Power Cable Traveling Wave On-Line Fault Location Technology Based On Wavelet Analysis

The power cables are used extensively with the merits such as small transmission pathway, high reliability, less influenced by environmental pollution and low maintenance workload. With the speeding up of railway construction, the utility proportion of power cable is averaging up in the railway power supply systems, and the probability of cable fault is also increasing which largely influences on the normal production and life. It gets more and more attention to adopt more advanced and precise cable line fault location technique used for fault location.Based on railway engineering, combined with cable fault type and reason analysis, this thesis carries on fault location by utilizing the traveling wave ranging principle and wavelet analysis technology.This thesis introduces the power cable fault location technology at home and abroad briefly, expounds cable fault types and causes detailedly. The causes mainly due to the quality of installation and construction, external force damage, the quality of cable and its accessories, etc.Afterwards, based on the analysis of the traveling wave fault location technique and wavelet transform theory, the pulse current ranging method is studied and pulse current ranging method wiring diagram is set up. The corresponding hardware equipments are selected and set function. This thesis adopts the double channel digital memory card as data acquisition unit, uses Rogowski coil as linear current coupler, and utilizes industrial control computer with reliable and stable performance as data processing module, output terminal, graphic user interface. On the basis of reliable data obtained, combined with the technology of software engineering, the software fault location system is designed; the data analysis and the concrete implementation are completed through hardware and software of integrated debugging.Eventually, by applying the device into practical engineering and contrasting fault location data measured on site and the actual fault location, it gets that the error is less than2.2%, which meets the desired goal and fully shows that the device meets the requirement of precision. The feasibility of the cable fault location system is verified by the case, which provides the practical and theoretical reference for power cable fault location in railway power supply system.