Abstract: In recent years, the installed capacity of new energy power stations has shown a rapid growth trend. Owing to the advantages of small land occupation, strong environmental adaptability and stable operation, medium-voltage power cables have become the preferred scheme for collector lines in new energy power stations, whose operation reliability is directly related to the operation efficiency of power stations. Taking medium-voltage cables in new energy power stations as the research object, this paper focuses on three major causes: poor construction technology, quality defects of cable joint fabrication, and inadequate operation and maintenance, systematically sorts out the corresponding typical fault types and formation mechanisms. Combined with actual engineering cases, it visualizes the fault hazards and occurrence processes, summarizes targeted fault troubleshooting methods, and finally puts forward optimization suggestions. The research results can provide technical reference for the construction, operation and maintenance of power cables in new energy power stations, and help improve the overall operation reliability of power stations.