Considering the existing problems of current Thevenin equivalent algorithms,a tracing algorithm of Thevenin equivalent that is applicable to power systems with large disturbance is presented.First,the potential voltag...Considering the existing problems of current Thevenin equivalent algorithms,a tracing algorithm of Thevenin equivalent that is applicable to power systems with large disturbance is presented.First,the potential voltage amplitude of Thevenin equivalent at the moment of fault is calculated with the parameters before fault.Then the resistance before fault and the potential voltage amplitude of the moment of fault is used to calculate other parameters of the moment of fault.The main steps of this algorithm are as follows:1)The resistance and reactance of Thevenin equivalent before fault are used as initial parameters.展开更多
A new method to evaluate the fitness of the Bayesian networks according to the observed data is provided. The main advantage of this criterion is that it is suitable for both the complete and incomplete cases while th...A new method to evaluate the fitness of the Bayesian networks according to the observed data is provided. The main advantage of this criterion is that it is suitable for both the complete and incomplete cases while the others not. Moreover it facilitates the computation greatly. In order to reduce the search space, the notation of equivalent class proposed by David Chickering is adopted. Instead of using the method directly, the novel criterion, variable ordering, and equivalent class are combined,moreover the proposed mthod avoids some problems caused by the previous one. Later, the genetic algorithm which allows global convergence, lack in the most of the methods searching for Bayesian network is applied to search for a good model in thisspace. To speed up the convergence, the genetic algorithm is combined with the greedy algorithm. Finally, the simulation shows the validity of the proposed approach.展开更多
文摘Considering the existing problems of current Thevenin equivalent algorithms,a tracing algorithm of Thevenin equivalent that is applicable to power systems with large disturbance is presented.First,the potential voltage amplitude of Thevenin equivalent at the moment of fault is calculated with the parameters before fault.Then the resistance before fault and the potential voltage amplitude of the moment of fault is used to calculate other parameters of the moment of fault.The main steps of this algorithm are as follows:1)The resistance and reactance of Thevenin equivalent before fault are used as initial parameters.
基金This project was supported by the National Natural Science Foundation of China (70572045).
文摘A new method to evaluate the fitness of the Bayesian networks according to the observed data is provided. The main advantage of this criterion is that it is suitable for both the complete and incomplete cases while the others not. Moreover it facilitates the computation greatly. In order to reduce the search space, the notation of equivalent class proposed by David Chickering is adopted. Instead of using the method directly, the novel criterion, variable ordering, and equivalent class are combined,moreover the proposed mthod avoids some problems caused by the previous one. Later, the genetic algorithm which allows global convergence, lack in the most of the methods searching for Bayesian network is applied to search for a good model in thisspace. To speed up the convergence, the genetic algorithm is combined with the greedy algorithm. Finally, the simulation shows the validity of the proposed approach.
