An Application Study On Capacitive Apparatus Insulation Monitoring System In 500kV Honggou Substation

Dielectric dissipation factor(tgδ) is a key parameter in capacitive power equipment insulation on-line monitoring,which can reflect the insulation station of the capacitive equipments such as Bush and CT.However,it is a challengeable task to measure tgδprecisely because many factors such as harmonic,DC offset,signal frequency fluctuation,random noise,ambient temperature and humid introduce considerable error to the measurement of tgδ.Therefore,tgδon-line measurement methods and devices have been a hot research task for many scholars in the field of power equipment on-line monitoring.In view of the current electrical equipment on-line monitoring system,a new strong anti-interference capability,high-precision measurement equipment insulation on-line monitoring system,CTM,through on-line monitoring the leakage current of the current transformer and capacitor bushing to response to real-time monitoring equipment insulation,at the same time it can monitor 120 CT or bushing.First of all,this article is a in-depth study of the dielectric loss angle and leakage current on-line detection of the power system bush,and other related high-voltage capacitor-based electrical equipment,brought forword on-line detection system CTM, and carried out the reaserch work.Secondly,the structure of capacitive on-line monitoring equipment,mainly include the sensors and the signal processing modules.At present,data communication using IEC60870-5-104 Statute(the Statute 104) and the of the 101 statute for communication.The sensor is the input of the insulation on-line monitoring analysis,the performance plays an important part of measurement accuracy,stability, reliability,as well as the follow-up analysis of the insulation state diagnosis of the whole system.Sensors realize the insulation leakage current measurement,mainly consist of logical meter,phase decoder,the terminal screen connector and environmental parameters,the four test modules.Signal processing module mainly include phase decoder and the central control room two parts;phase decoder is used to encode the collected leakage current signals.Central Control Room consists of the host, synchronous control sub-system,A/D sampling sub-system three parts.Synchronous control sub-system is responsible for the entire station synchronous sampling and sync functions;A/D sampling sub-system is responsible for the sampling function;host system is mainly responsible for data acquisition control,data processing,task management and communication task management,receive various kinds of data transported from on-site monitoring equipment,and calculate the dielectric loss and leakage current of the equipments.The paper tested the system finally,the test results showed that:the high-voltage capacitor of bush-insulated electrical equipment sensor has good measuring accuracy and linearity;it accurately captures the insulation deterioration information of operational current transformer,complete the processing and identification of information by the processor.The system is designed with a user-friendly software interface,the diagrams output,truly and intuitively response to the current transformer operation state,provide an effective security measures for the operational high-voltage current transformer,which will effectively promote Honggou substation grid equipment management model transform from regular-based test to condition-based maintenance model.