Study Of Power System Reliability Evaluation Considering Maintenance Strategies And Communication Failures

With the development of science and technology,the equipment and technology used in power system have undergone tremendous changes.Traditional maintenance methods have been unable to adapt to the changes of the times.In order to improve the quality and efficiency of power system maintenance,the maintenance strategy and equipment update strategy should be strengthened on the basis of necessary monitoring and risk assessment of power system.With the extensive application of communication equipment and intelligent substation,more and more attention has been paid to the internal faults in the substation.Under the background of the gradual digitalization and intellectualization of the power system,the lack of consideration of the failure of components in the substation will affect the accuracy of the reliability evaluation of the power system.This thesis uses probability mathematics method to study the reliability-related problems of power system considering maintenance strategy and communication failure.The following work has been accomplished:(1)In view of the shortcomings of the maintenance strategy model in the practical application of power system reliability evaluation method,a power system reliability evaluation method considering maintenance strategy is proposed.This method assumes that the operation status of power system equipment cannot be accurately known.According to the aging fault rate curve based on equipment belief,the equipment aging model based on maintenance strategy is established.On the basis of considering both accidental and aging faults of components at the same time,a strategic maintenance model considering both failure modes is proposed.Aiming at the uncertainty of condition monitoring,equipment belief is used to replace the accurate state of the system to characterize the aging grade of the system equipment.The aging failure of components can be prevented by optimizing maintenance strategy.By evaluating the reliability index of the system,the overhaul strategies are compared and analyzed,the alternative overhaul strategies are evaluated comprehensively.(2)To overcome the shortcomings in the speed of power system reliability evaluation based on complex multi-state model,a fast reliability evaluation method of load power system based on Line Sampling Simulation(LSS)is proposed.This method uses straight line instead of random point to sample high-dimensional space,and increases the probability of rare event sampling to improve the efficiency of reliability evaluation.The traditional Monte Carlo evaluation method is used to remodel the sampling space by sampling from the state space at random.Then,a line sampling path is formed via the important direction of line sampling.The speed of power system reliability evaluation is greatly improved to adapt to the reliability evaluation model taking into account the maintenance strategy.While considering the technical constraints of maintenance abality,the equipment replacement strategy is reasonably evaluated to ensure the safe and reliable power supply of the power system.(3)In view of the shortcomings of the reliability risk assessment method of intelligent substation in practical application,a reliability analysis and assessment method considering the risk dependence of power system information link is proposed.This method aims at analyzing the interdependence between communication network and power system,and combs the internal structure of substation by studying the communication information link of substation.The reliability failure state model of equipment in the station is established considering the characteristics of communication equipment delay condition.A set of substation failure events is established via sorting out the types and consequences of substation failure events.While evaluating the reliability of substation system,the system topology is corrected by using the subset of equipment faults in substation,the failure model of power system caused by communication faults in substation is analyzed,and the reliability index of system is calculated,so that the reliability evaluation and analysis of power system considering the internal information link of substation can be realized.(4)To overcome the shortcomings of reliability evaluation rate for complex multi-node power systems,a hybrid power system reliability evaluation method based on Spliting Method Simulation(SMS)is proposed.The basic idea of this algorithm is to divide and progressively sample the system state space,replicate the important sampling points,and focus on exploring the small probability failure area.By improving the sampling efficiency of rare faults,the fast evaluation of power system reliability can be realized.In the process of applying SMS to power system reliability evaluation,by establishing redundant generating capacity,quantitatively analyzing system security status,self-generating adaptive progressive failure area is realized.Rare event samples are efficiently generated by Gibbs sampling method,which significantly improves the sampling efficiency and achieves fast and efficient reliability evaluation of power system with rapidly increasing number of nodes.