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As the power control technology of wind farms develops, the output power of wind farms can be constant, which makes it possible for wind farms to participate in power system restoration. However, due to the uncertainty of wind energy, the actual output power can’t reach a constant dispatch power in all time intervals, resulting in uncertain power sags which may induce the frequency of the system being restored to go outside the security limits. Therefore, it is necessary to optimize the dispatch of wind farms participating in power system restoration. Considering that the probability distribution function (PDF) of transient power sags is hard to obtain, a robust optimization model is proposed in this paper, which can maximize the output power of wind farms participating in power system restoration. Simulation results demonstrate that the security constraints of the restored system can be kept within security limits when wind farm dispatch is optimized by the proposed method.

Aiming to provide semantic information for decision supporting system and constructing a domain knowledge base in which knowledge is represented in a formalized form so as to be understood by machine, this paper suggest a new method which is based on conceptual graph to represent knowledge formally. At first, the system architecture would have been designed, and it consists of knowledge acquirement layer, knowledge management layer and knowledge application layer. Then, the crucial technology, formalizing the domain text by conceptual graph, is expatiated by the domain ontology and knowledge is constructed synchronously. By using the specific computational tool named Prolog+CG for representing and reasoning about water conservancy texts, the validity and efficiency of this method are proven.