The Adaptive Protection Of Power System Research Based On Wide Area Networks

With the continual enlargement of power grid scale, the structure and operation mode are becoming more and more complex, which puts forward higher requirements for relaying protection. Whether the protection system can actualize the equirements or not depends on its collection information,protection principle,operating criterion,and the value setting. Because traditional line protection adopted one fixed value for all kinds of operation mode strategies, it has no adaptive ability when operation mode changed. As the value settings used local data, it made setting calculation and fixed value checking difficult. This paper analysis the current operation state based on whole network, which make real-time and adaptive settings come true, and the relaying protection can work in best state.Because the real-time adaptive settings have to combine with current operation mode, dynamic grid topology analysis becomes one of the key issues. In this paper, two topology analysis methods are introduced. One is the topological analysis of the static grid based on expanding adjacent node, the other is the topological analysis of dynamic grid based on local topology modifying. It is proved by example that the methods have the advantages of simplicity,small amount of calculation,and easy coming true. The target of adaptive protection based on WAN is setting adaptively for fixed value, this paper introduced two adaptive settings algorithms based on switch changed position and line fault separately. It is proved by simulation that combing with system operation mode switch changed position arithmetic extends II scope of protection in the protection of the co-ordination relations, has more sensitivity in satisfying the selective premise. And it is also testified that line fault arithmetic has strong adaptive capacity and more sensitivity to adjacent lines, and it's protected scope is broader than traditional scope of protection.