At present, some technologies and equipment in power system are actually involved in condition monitoring to some extent, especially some online monitoring systems and fault diagnosis systems. Although these systems can play a certain purpose of condition monitoring, they can not fully meet the requirements of condition monitoring. Internationally, condition monitoring has become an active new branch of nondestructive testing. Since 1989, many international conferences on condition monitoring have been held, and a large number of research reports and academic papers have been published every year. In the field of power system, condition monitoring has been paid more and more attention by management, scientific research, operation and engineering maintenance personnel of power department, and has gradually become an international frontier research topic and research hotspot.

According to different power equipment, people have put forward many condition monitoring methods, many of which are universal, such as vibration analysis, gas in oil analysis, partial discharge detection, insulation recovery voltage method and so on.

Under normal operating conditions, power equipment has an inherent natural vibration level. When the fastening screw becomes loose or changed, or the winding or lead structure deviates or is disturbed due to short circuit and insulation aging, the vibration of the equipment will be aggravated. Vibration analysis method is widely used to monitor this kind of fault. In order to monitor the vibration level of equipment, acoustic sensors and accelerometers are often used to collect the vibration signals of equipment, and then the intensity and vibration mode of the vibration signals are analyzed and discriminated, so as to achieve the purpose of monitoring the state of equipment.

Gas analysis in oil is one of the most commonly used methods for insulation monitoring of oil-bearing equipment (such as transformers). Because different faults in equipment will produce different gases, such as acetylene gas produced by arc and carbon monoxide produced by overheated fibers, the purpose of equipment insulation diagnosis can be achieved by analyzing the composition, content and relative percentage of gas in oil. Several typical gases in oil, such as H2, carbon monoxide, methane, C2H6, C2H4 and C2H2, are often used as characteristic gases for analysis. After detecting the composition and content of each gas, the characteristic gas method and