Research On The Communication Mode Of Point To Point Trip With Extension Bridge Connection In Intelligent Substation

With the development of power grid, its scale and structure are also continuously expanded and perfected, leading to higher requirements for the efficiency, reliability, control and protection of the power grid and equipments. Various equipments are technologically upgrading, and what is worth mentioning is that relay protection and the improvement of the network communication implementation model have entered the stage of the digital and intelligent. Nowadays, with the development of equipment for protection, measurement and control, communication, as well as data collection in substation, the requirement for equipment compatibility is increasingly high. In such situation, the international electrotechnical IEC61850 standard is regarded as the unified communication standard, unifying the transmission and transformation protocol of communication automatic system and closely linking the generalized quadratic equipments of the substation together. This paper mainly analyzes how to integrate the substation communication system and delay protection, and through the optimization of system information hierarchy and unified modeling, further selects communication network method and puts forward perfect communication framework model.In the designing scheme of intelligent substation, the reasonable selection of communication system matching method within the station is particularly important, as it will directly affect the protection of those fast, accurate and reliable actions. This paper mainly analyzes and puts forward the SV point-to-point tripping communication mode required by intelligent substation. GOOSE network tripping is "point-to-point" tripping mode which should strictly abide by the principle of "direct sampling direct tripping". Moreover, the paper presents an effective mode that is different from network tripping. "Point-to-point’tripping can avoid the influence caused by switch delay through increasing the fiber optic patch cables, which effectively improves the reliability and rapidity of protection.This paper intends to adopt the following methods in research:the theory study, scheme introduction, scheme optimization, as well as scheme comparison between the original one and the improved. Currently, Xiamen power grid is vigorously constructing the intelligent substation, and most of the 110KV substations use typical connection mode of expanding outside bridge. The hierarchical structure of intelligent communication system for the 110KV Dongzhai substation is established on the base of IEC61850 standard, and the whole station follows a unified model consisting of station layer, spacer layer and process layer. Spacer layer connects and transfers information with the station controlled network through MMS network, realizing such operations as transmitting state alarm information of each protection interval, collocating protection parameters, switching constant value, setting and canceling.Taking the intelligent substation construction in Xiamen as an example, this paper mainly introduces the matching method of typical process layer in the process that substation automatic system realizes the relay protection function, discusses the "direct sampling direct tripping" principle specified by national grid, and also puts forward a network matching optimization scheme combining with the practical situation. The paper studies the specific implementation mode of relay protection communication by adopting the typical main connection (expanding outside bridge connection) point-to-point tripping within intelligent substation, and further analyzes and testifies the correct operation of relay protection in this network configuration mode by the actual debugging data. In the end, the paper puts forward the unsettled questions and research suggestions relating to this subject in China recently, which points out the direction for further researches.