Research On Distribution Network Operation Risk Transmission And Decision Making Model As Well As Information System

As an important part of power system,distribution network provides power to power users through direct connection,so it plays an important role in power supply security for users.Historical data show that 80%of the power outage events in the power system are caused by distribution network failure.Therefore,the risk management analysis of distribution network operation process plays an important role in power network security.With the introduction and development of Energy Internet,the high integration of power flow,information flow and value flow provides a good platform for the development of power system,but at the same time,it also injects more uncertainty into the operation and management of distribution network,and the dynamic and transmissibility of risk factors are more obvious.In view of the new situation,starting with the operation process of distribution network,this paper carries out risk transmission and optimization decision-making modeling analysis from four aspects of information security risk transmission,power failure risk,failure recovery and maintenance decision-making,and then discusses the distribution network operation risk management information system based on theoretical model.The main achievements are as follows:(1)Research on distribution network information security risk transmission considering cyber physical fusion.Cyber-physical system is a new type of integration system with the development of Energy Internet.The cyber physical fusion accelerates the intelligent development of power grid,and also increases the potential risk of power grid operation.With the interaction of information,the transmission and diffusion effect of risk will be more prominent.Aiming at the high dimensional and small sample data of distribution network,a distribution network risk transmission model based on knowledge element is established.In this model,monitorable data in physical system is used as input data to express the transmission distribution network risk,and a standard risk level system is constructed according to the internal state attribute threshold of carrier knowledge element.The projection pursuit method is used to find the best projection of the input data and the dimension is reduced.Furthermore,according to the risk element transmission theory,the probability and risk distribution of monitorable sample risk transferring to the total risk level of distribution network are calculated,and the risk transmission effect is analyzed.(2)Research on the power failure risk assessment of distribution network considering failure loss.Firstly,the power outage risk analysis of distribution network is carried out,including evaluation index system and risk evaluation model.Secondly,the failure rate model considering the influence of natural environment is established,and the idea of distribution network failure block partition and the method of distribution network failure outage probability estimation based on feeder partition are proposed.Based on the idea of risk element transmission,a calculation model of power failure loss risk in distribution network based on risk transmission is proposed.Finally,the load outage probability,user outage time,user loss,power supply enterprise loss and distribution network loss are calculated by using an example,and the influence of risk transmission loss on different types of users is analyzed.(3)Research on distribution network failure recovery decision-making considering subjective risk.In order to quickly and efficiently restore power in the non-failing power loss area,based on heuristic rules,a failure recovery scheme set is rapidly formed according to the failure recovery target and five decision indices of load recovery amount,load transfer amount,load capacity margin,switching operation times and load balancing rate.For real-number recovery schemes,considering the interaction between attributes and the consistency of expert group evaluation,the Shapley value of index is defined by Mahalanobis-Taguchi system and interval fuzzy preference matrix.The fuzzy measure is determined by Shapley value,and the fuzzy decision model is constructed using function.For interval number failure recovery schemes,the interval number decision vector is regarded as a hypercube in the multi-dimensional attribute space,and the two-level orthogonal test is adopted to uniformly and dispersedly distribute the points on the hypercube,and the point set is formed to represent the decision scheme according to the test times of the orthogonal table.The Mahalanobis distance is used to calculate the distance between each scheme and the positive and negative ideal solution to eliminate the influence of the correlation between the indices on the results.Considering the subjective risk attitude of company leaders,a grey relational function based on Mahalanobis distance is defined by introducing cumulative prospect theory.Then the positive and negative prospect value matrix is constructed,the comprehensive prospect value of failure recovery scheme is calculated,and the optimal solution is selected by sorting.(4)Research on optimization decision-making of distribution network maintenance considering risk assessment.Taking maintenance risk and failure risk as the double objectives of distribution network optimization,and taking maintenance time and mode as optimization variables,a multi-objective optimization model is constructed.The Pareto non-worst solution set is obtained by the multi-objective particle swarm optimization algorithm with crowding distance sorting.Considering the subjective risk attitude of decision makers,a multi-attribute decision-making method based on trapezoidal intuitionistic fuzzy numbers with different risk attitudes is proposed.The improved Bonferroni operator is used to fuse scheme values;the maintenance schemes are sorted by risk expectation;the maintenance results under different risk attitudes are obtained.(5)Research on the design of distribution network operation risk management information system.The theory and model are extended to the actual distribution network management,and the design of distribution network operation risk management information system is proposed.On the basis of requirement analysis,the design structure and function of the system are studied,and the key technologies required for system construction are discussed.