A Research On A New Wide Area Backup Protection

Conventional line backup protection relays protect a constant area through the cooperation of the action time, action value and action region. With the increase of the power system capability and the complicated system structure, it troubles the cooperation of the protection value and action time. Studies of significant power system incidents indicate that protection relays are involved in most of the major disturbances, even making the system breakdown. With the development on computer and communication, the wide area protection can solve the problem above excellently, it is different from conventional protection relays, through collecting the fault information and the switch information, working out the action strategy that is optimized and harmonized.In the beginning, the background and research situation of the wide area protection are introduced in this thesis, and then characteristics, function making up, function partition and system structure are discussed. On the basis of the analysis of the flaw of the conventional protection relays, a new wide area transmission line backup protection scheme is proposed in this dissertation, and then the theory, purport, system structure and protection arithmetic are introduced. The fault phase selection includes current phase selection and impedance phase selection, and the fault location contains current direction element and impedance direction element, and then the idiographic method is given.The wide area backup protection proposed in this dissertation consists of the protection master system and the protection slave system. The function distribution, the design of the hardware and the software of these two parts are introduced in this dissertation. On the aspect of hardware, the characteristics and function distribution of the variant of template used in the wide area protection relays are presented in the thesis, and the APCI5000 industrial computer, which is the core of the hardware is also introduced. On the aspect of software, the frameworks of the protection master system and the protection slave system are given, and then the program flows are introduced detailed. Finally, the dynamic simulations show practicability of the proposed scheme.