Development Of Integrated On-line Monitoring System For Operating Environment And Partial Discharge Of High Voltage Switchgear

As an important equipment in power system,the safe and stable operation of switchgear is very important to the whole power system.In order to improve the stability of switchgear operation,this paper studies the partial discharge and environmental regulation during the operation of switchgear.On the one hand,insulation aging may lead to partial discharge,and partial discharge may further deteriorate insulation aging.In the long run,breakdown,fire and other faults may occur.The partial discharge detector of switchgear can check the partial discharge,but it is difficult to detect the partial discharge fault in time because of the limited frequency of detection and the limited amount of data collected.Therefore,this paper designs an on-line monitoring system for partial discharge in switchgear,which can detect partial discharge faults in time,eliminate hidden troubles and prevent them in the future.On the other hand,environmental problems such as excessive temperature rise,excessive humidity,condensation and so on are also a major problem that troubles the operation of switchgear.Especially in high temperature,high humidity and high load summer,these problems are particularly serious.There are air conditioners,dehumidifiers,fans,heaters and other environmental adjustment equipment installed on site,but the effect is limited.Therefore,this paper also realizes on-line monitoring function of switchgear operating environment,comprehensively adjusts and controls all kinds of environmental adjustment equipment,and reduces the occurrence of condensation and other problems.In terms of hardware,this paper adopts modular design,which is divided into three modules: switch cabinet ultrasonic and temperature and humidity monitoring module,switch room temperature and humidity monitoring module,and environmental control equipment control module.These three modules can be freely combined to meet the needs of different scenarios.On the basis of realizing monitoring function and according to the requirement of field use,this paper focuses on improving the sensitivity and anti-interference performance of partial discharge ultrasonic signal detection,the stability of wireless transmission system and the overall stability of hardware system,and strives to reduce costs,reduce the difficulty of generation,installation and maintenance,in order to reduce obstacles for large-scale promotion of on-line monitoring system for switchgear.In terms of software,the main functions of the monitoring software designed in this paper are to view the partial discharge information and temperature and humidity information of switchgear in real time,to automatically warn the fault information,to record normal and fault data,and to control the environmental adjustment equipment.The software adopts browser/server architecture,and users do not need to install the software,so it is more convenient to use.It can view data according to multi-dimensional and multi-chart of region,equipment,time and data type,so as to accurately grasp the operation status of switch cabinet.All equipment and data are managed by region list to reduce the difficulty of operation.In terms of data processing,a method for identifying and classifying ultrasonic image of partial discharge in switchgear based on short time Fourier transform and sparse representation is proposed to accurately identify and classify the partial discharge faults.The one-dimensional ultrasonic waveform is converted into two-dimensional time-frequency chat by short-time Fourier transform.Sparse representation algorithm is used to recognize and classify time-frequency chat.The experimental results show that this method can accurately identify and classify partial discharge signals,and the effect is better than the traditional method.