Reliability Assessment Of Cyber Physical Distribution System And Its Application

With the wide application of information and communication technology in power network,the coupling between cyber system and power physical system is further deepened.In the Cyber Physical Distribution System(CPDS),fault handling of the distribution networks is highly dependent on the correct judgment of the cyber system.Therefore,in order to accurately reflect the real state of distribution networks,cyber fault or failure has also become one of the potential risks that threaten the safe and reliable operation of the power networks.Therefore,the reliability assessment of distribution system needs to take into account the influence of cyber system.At present,the research on reliability evaluation of CPDS focuses on Centralized Feeder Automation mode,and Distributed FA(DFA)is seldom mentioned.However,distributed FA is widely used in practical engineering due to its characteristics of short communication delay and strong topology adaptability.Therefore,this paper studies the CPDS power supply reliability evaluation based on DFA.Firstly,this paper introduces the structure of CPDS and the DFA system and analyzes the influence of the power supply reliability when the DFA information system is abnormal.Then,the reliability models of intelligent electronic devices and communication networks are built and incorporated into switch decision models based on the fault handling mechanism in DFA mode.Second,due to the strong ability of simulation method to adapt to complex scenes and restore the reality,this paper use the sequential Monte Carlo method to evaluate the reliability of CPDS.Through the terminal function of DFA and neighborhood interaction process of local information,regional decision relational matrix is used to analyze the power supply reliability influence of different cyber faults in the fault handling process of distribution network.In order to further improve the calculation efficiency,the decision state of switch is transformed into the probability model of operation state,which is used to discribe misoperation and rejection of switches.Then,based on the least path method and the fault processing process,the physical system components are divided into four categories,and the load equivalent failure rates and the equivalent outage time in CPDS and the system reliability indices are calculated,so as to realize the reliability assessment of CPDS by analytical method.Finally,a case study is given to verify the efficiency and correctness of the proposed algorithm.To realize the engineering application of the reliability assessment of CPDS,this paper generalizes the proposed method based on the actual scenario,and forms the practical algorithm of reliability assessment for multiple feeder automation modes and multi-tie switch in complex distribution networks.In the transformation planning of the current distribution network,this method can be used to optimize the configuration of the "three-remote"terminals for the existing switches.It can consider both power supply reliability and economic benefits,so that it can increase the overall benefits of the distribution network planning scheme.Finally,this method is applied to the "three remote" terminal configuration planning for feeder switches in a city,which verifies the feasibility of the method in distribution networks transformation planning.