Design Of Circuit Breaker On-line Monitoring Device Of Intelligent Substation

Circuit breaker is the most important control and protection equipment in powersystem, by whose operational status the security and stability of the power system isaffected directly. Along with our electric power system towards the direction of highvoltage and bulk, as well as intelligent substation continuous construction, thereliability of the circuit breaker the power system is put forward to extremely strictrequirements. The "regular maintenance" widely used currently can not meet thedevelopment of the power system and satisfy the construction of smart grid now. It isinevitable for condition-based maintenance of circuit breakers to rely on the breakeronline monitoring technology.This thesis mainly considering the mechanical characteristics monitoring ofcircuit breaker as the goal introduces the monitoring principles of closing coil current,energy storage motor current, moving contact travel characteristics and auxiliarycontact detailedly, and describes how to calculate mechanical properties parametersthrough the closing coil current wave curves and moving contact travel timecharacteristic, including opening time and closing time, the maximum current ofopening and closing, stroke, three-phase main loop current, over travel and empty run,etc.Then, the paper gives the overall design of the circuit breaker on-line monitoringdevice in smart substation, it is through the hall current sensors to observe the closingcoil current, three-phase main loop current and energy storage motor current, andthrough rotating photoelectric encoder to get the characteristics of moving contact.The hardware and software designs of circuit breaker online monitoring device in theintelligent substation are based on the TMS320F28335, which is a chip that providesrich integrated modules, reducing the peripheral circuit design. In the architecture ofthe intelligent substation, circuit breaker online monitoring device belongs to theprocess level, and primarily takes responsibility for the acquisition of the parameters,also establishs the communication with circuit breaker IED in the bay level throughthe CAN bus. In addition, following the needs for building of the intelligentsubstation, the calculation of the various mechanical characteristic parameters is transplanted to the circuit breaker monitoring IED, then, the results are transported tothe On-line monitoring expert software in the substation level by protocol ofIEC61850. All kinds of visual function, state evaluation of circuit breaker operationand data display in the circuit breaker on-line monitoring device are mainly achievedby the On-line monitoring expert software of the station control layer, while in thisproject, they are carried out through intelligent power transmission and transformationmonitoring and decision system. Moreover, intelligent substation circuit breakeron-line monitoring device realizes clock synchronous with IRIG-B after receivingGPS signals via station level. The system had been successfully installed in Hongqiao220kV substation, which has now passed the acceptance and put into operation.Intelligent substation is an important part of the smart grid, its requirements ofthe development make an certain trend for high voltage primary equipments, in whichthe circuit breaker online monitoring technology is the key technique. With thecontinuous development of the smart grid, it is becoming the main development trendfor high-voltage primary devices in the future substation to take on-line monitoringtechnology into primary equipment and create intelligent equipment of compact type.Therefore, it is very important to study the online monitoring of circuit breaker.