Research On Wide-area Protection Based On Wide-area Measurement Information Of Power Grid

With the development of the nation-wide interconnection in China, the power grid scale is becoming larger and the operation mode is becoming more and more complex. It is more important to power system protection and stability control. In recent years, the blackouts occurred around the world reveal that there is lack of cooperation between relay protection system and antomatic safety devices. It is also realized that relay protection and automatic control must be strengthened from the point of view of whole network or regional network. The reliability of relay protection must be improved, further more, it is necessary to make relay protection and automatic control devices work cooperatively to enhance power system stability after fault. Based on wide-area measurement information of power grid, wide-area protection system(WAPS) finds a new way to deal with cooperative issue between relayprotection system and automatic safety devices in large power system. It leads the development of relay protection in future.In this thesis, the significance and research progress of WAPS based on wide-area information of power grid are introduced at first, then basic discipline of WAPS is expatiated. Wide-area measurement information of power grid is used for enacting protection strategies in WAPS, so it could make protections located at different positions in power grid work cooperatively. After analysis on availability of wide-area information in protection system, building WAPS to defend three different types of power system stability problems is presented, and two functions of WAPS, wide-area backup protection and wide-area emergency control, are expounded in the paper.Wide-area backup protection(WABP) is the primary research content in this paper. Centralized configuration or distributed configuration could be adopted for WABPS. The author put forwards a new topological structure which is composed of concentrated mode and distributed mode, concentrated- distributed mode. Then the improvements in protection of WABPS are discussed.Arithmetic of WAP refers to several fields including relay protection and emergency control. In this paper, arithmetic of WABP is the research emphases. There are several subjects: Intelligent Electronic Device (IED) relationship coefficient matrix mathematical derivation based on basic disciplines of Petri Net, some operation criterions of WABP based on startup information, output information of relay protection and circuit breakers state which are located at different positions in power grid, wide-area current differential backup protection composite criterions based on current instantaneous values differential, etc.At last, a design scheme of WABPS based on ethernet and SDH fiber ring network is presented in the paper. Then, the author designs communication network of WABP. The hardware system of IED based on multi-CPUs cooperative mode is designed as well.