Purpose/Aim
High voltage switchgear failures occur frequently, most of the high voltage switchgear accidents are caused by partial discharge. Current switchgear condition monitoring mainly focuses on partial discharge signal monitoring, and lacks comprehensive monitoring of multi-state characteristics of switchgear. The multi-state feature monitoring of switch cabinet is bound to form massive data, which can more effectively realize the economic, scientific and intelligent detection and diagnosis of switch cabinet operation state. Therefore, the design of on-line monitoring system for switchgear with multi-state characteristics is very necessary.
Experimental/Modeling methods
The CPU system, sensor sampling module, signal conditioning circuit module, wireless transmission module and power system are designed and integrated into the hardware system of the monitoring system. The software is written by Keil uVision5 software to realize the communication between the monitoring device and the oneNET cloud platform. The switch cabinet status monitoring and storage are realized through oneNET cloud platform. According to the common discharge model of switch cabinet, three typical defect models are designed and manufactured, and the partial discharge measurement platform of high voltage switch cabinet is built. The typical defect discharge model is tested by the monitoring system to verify the effectiveness and reliability of the monitoring system.
Results/discussion
Through the field application of the monitoring system, the state of partial discharge, ozone, temperature and humidity in the switch cabinet can be displayed and stored in oneNET monitoring platform in real time. The verification shows that the system has strong anti-interference ability and high detection sensitivity.
Conclusions
（1）This device can effectively measure the partial discharge phenomenon on the high-voltage switchgear, improve the accuracy and reliability of the partial discharge data acquisition of the switchgear, and realize the automation and intelligence of the partial discharge life cycle monitoring of the switchgear.
（2）The system can effectively solve the requirement of data quantity and data comprehensiveness in switchgear insulation state analysis, and provide reliable data guarantee for insulation state analysis.
 

High voltage switchgear,partial discharge,monitoring