This manual has twelve chapters, which mainly describe the abnormal phenomena and accident causes that occur during the operation of power equipment such as power transformers, transformers, lightning arresters, power cables, power capacitors, high-voltage switchgear, high-voltage motors, generators, etc., And point out how to deal with them. The manual also introduces the safe operation of the grounding network, accident causes and preventive measures for overhead line insulation and external substation insulation, secondary circuits and their troubleshooting methods, and the application of power infrared diagnostic technology. In order to meet the work needs of technicians in electrical operation and maintenance, the appendix also contains a summary of the regulations and standards related to abnormal operation and accident handling of power equipment. This manual lists many examples in its explanation. Abnormal phenomena, accident causes and treatment methods are tabulated. It is rich in content, highlights physical concepts, and integrates theory with practice. This manual can be read by engineering and technical personnel involved in operation, maintenance, installation, testing and management of power systems. It can also be used as a reference for manufacturing departments, power users and relevant professional teachers and students in universities and technical secondary schools.