Research On Residual Current Protection Monitoring System Based On Comunication Protocal Of National Power Industry

The development of smart grid has proposed new requirements for switching equipment in low-voltage distribution network. Traditionally, the residual current operated protective devices are not only necessarily used to prevent power lines from being damaged, but also widely used to protect people from being harmed by high voltage electric shock. Residual current devices of Smart Grid have the advantage of traditional circuit breaker. Moreover they have much more functions, such as the function of communication connections, information exchange as well as data logging. These advanced features are invented to adapt to the intelligent power system.The monitoring center is the core of the smart residual current protection monitoring system. Residual current operated protective devices in the monitoring system are all under the control of the monitoring center. The method of connection, the choice of the development platform, the design and the programming of the system as well as some other issues are solved in this paper. First, based on the communication protocol of national electricity industry standard, the author determined the command information which would be sent to the circuit breaker from the host computer. Secondly, the analysis for connection modes and actual demand lead to the selection of RS485 communication bus to be used as the data transmission channel between the host computer and the circuit breaker. Lastly, the paper chose LABVIEW as the platform for programming the monitoring system.Compared with all of the previous communication protocols, communication protocols based on the national electricity industry standard includes more comprehensive monitoring functions, and these functions are more specific. Furthermore, the system also added a variety of practical functions according to actual needs during the process of design and programming. The main interface of the monitoring system can ask the important parameter of the each circuit break by turns, and when it comes to the interface of single circuit breaker under certain address, the significant parameters and protection events are being asked by the monitoring system repeatedly. The monitoring system has the function of data storage. The desired database is stored in the corresponding table.