Research On Fast Reliability Evaluation Of Composite Power System

Power system reliability evaluation, which constitutes an important basis for power system planning, design, operation and maintenance, comprises two main methods: analytical and Monte Carlo simulation (MCS). MCS are more often used for complex power system particular with the increasing penetration of wind, photovoltaic arrays and other renewable distributed resources while the efficiency of analytical one decreases when facing the difficulties. However, the rapid development of power systems with more reliable performance i.e. failure states has little probability of occurrence, leads to the recognition that the computational effort of MCS does increase. The design of a power system with high penetration of renewable energy is more complex due to the huge number of random variables involved and the fluctuating capacity levels of these sources. The need to release the burden is gradually becoming a cause for concern. The major of the work, that has previously been reported to achieve convergence quickly, aims at reducing states of the power system and improving the efficiency of generation redispatch and load-shedding procedures. The general principles, algorithms and implements mentioned in previous work are described in detail firstly in this paper. Based on cross-entropy concept, this paper presents a new method using dynamic failure set in the process of reliability evaluation, where emerging failure state is used to update the dynamic fault set after comparison. Optimal power flow is required if necessary then updating the dynamic failure set. Therefor times of executing OPF has greatly been reduced. The proposed method is tested using composite power system:IEEE-RTS 79 and IEEE-RTS 96 in non-sequential and Sequential simulation separately. The results indicate the rationality and validity of the proposed method.Finally, the proposed method was well applied to composite power system reliability evaluation which was tested on the practical power grid in China. In summary, to adopt the improved approach of sample can increases the simulation speed of Monte Carlo method in the reliability evaluation of power system. The methods given in this paper can be widely used for composite power system.