The Researching Of The Bus And Line Protection Based On Digital Substation

As the network technology、 computer technology and communication technology rapid development, the digitized substation is divided into the layer of stand accused、 the spacer and process with IEC61850.The data exchanges and communicates between the layer and the layer. The bus protection of the tradition can not meet the requirement of the development of the electric power system because of the traditional substation can not sharing and interoperate.The paper analyzes the characteristics of the distributed the bus protection scheme and puts forward the approach to adapt line backup protection automatically and cooperate with safe and automatic devices based on the information sharing of digital substation, which could solve the problems of the centralized the bus protection and line backup protection in an even better fashion.First of all, to analyze and compare between the centralized bus protection and the IEC61850distributed bus protection scheme, and point out the high reliability and flexibility of the distributed bus protection. Because the function of distributed bus protection be put down to the transition layer, so, it won’t cause the resection of all the branches connected to the bus when the bus protection occurs calculation errors or be disturbed or misoperation, and the distributed bus protection scheme can adapt to the change of the connection mode of the bus.Second, since the traditional line’s backup protection can not adapt to the change of the system operating mode, and it lakes of coordination with the safe and automatic devices, so if a line were jump and open due to the line faults, it can easily cause the concatenate circuit breaker tripped accidents of the associated electric components. The author put forward the self-reacting backup’s protection scheme of on-line modification of protective setting value, backup protection and measures of resection excess load cooperated with safe and automatic devices based on theoretical analysis and the application of the electric system’s simulation software PSCAD/EMTDC to do the digital simulation to the bilateral power source’s double lines. Therefore, it can effectively prevent the concatenate circuit breaker tripped accidents caused by tide transfer, and guarantee the stable operation of the electric system.