Research On The Partial Discharge Signal Characteristics And The Joint Detection Technology Of Switchgear

As an important device in power system,switch apparatus controls the connection of circuit,insulates the fault,thus protecting the power grid and other electrical equipment.Switchgear is a kind of switch apparatus widely applied in city grid.Its operation status directly influences the safety of grid.However,the switch apparatus may have some inevitable insulation defects due to the process of manufacture,transportation and installation,which are the main factors leading to partial discharge(PD).If the defects are not be found and eliminated in time,it is very likely to cause accidents such as power outages in large area.Therefore,it is necessary to monitor the insulation condition of switch apparatus.One of the effective methods is the PD detection.In order to develop the existing on-site detection technology,this paper studies different partial discharge detection methods of switchgear.Based on the advantages and disadvantages of transient ground voltage method,ultrasonic method and ultra-high frequency method,a suitable joint detection technology is proposed.In order to provide references for defect identification and to provide signal source references for related instruments and test platform,a partial discharge detection system for switchgear is built in this paper.Four defects models are physically simulated,including metal tip,suspended electrode,free metal particles and solid insulated air gap.Thus in the laboratory environment,the partial discharge signal characteristics of switchgear under different internal defects are summarized.In order to solve the problem that the on-site online monitoring device has a high cost and the live detection device is not portable enough,an innovative online detection system suitable for various operating conditions is developed,thus comprehensively improving the on-site detection quality of the partial discharge of switchgear.In order to verify the effectiveness and practicability of the joint detection technology in the on-site live detection of switchgear,as well as the reliability and flexibility of the new wireless on-line monitoring system of switchgear,this paper executes the tests in the field.The abnormal discharges are found by the developed monitoring system,the discharge types are recognized and the discharge sources are located by the joint detection method.