Reliability Evaluation Of Transmission System Base On Component Vulnerability

It is one of the most important thing to ensure the reliability of power system that evaluate the reliability of power system reasonable and scientific.In addition to the high probability events,the key components failures influence the reliability level of power system.The new method combine vulnerability analysis and reliability assessment are proposed in this paper to accelerate the convergence speed,reduce evaluation time,and improved the accuracy of reliability assessment.In this method,the key components of transmission system is identified by system vulnerability analysis.System state is selected by the important factors of transmission components.Vulnerability identification method is proposed based on absolute power betweenness.Considering the impact of absolute value of power flow,the load rate and property of the nodes,the absolute power betweeness is defined to identify key branch statically.The correlation between power flow of branches and the rules of power flow transfer are taken into account to define the distribution correlation factors to identify key branch dynamically.The computation speed and accuracy of branch identify are improved by this method.The dynamic structural identification can be fast achieved after the grid changes.The method considering the risk to identify vulnerability of power system is presented in this paper.A simplified calculation method for the distribution coefficient of power flow transfer is proposed.With the branch load factor and the historical failure rate,the branch probability important factors are defined from the perspective of risk defines.Integrated the depth and breadth of branch to be used in power transmission between power and load,branch power distribution betweenness is defined to describe the structure importance of branch.The structure and probability important factor is proposed base the two factors above,to indicate the power system from the probability and the influence of events to identify the vulnerary branch with higher fault probability.Based on the power system vulnerability,the power system reliability evaluation method is proposed.Monte Carlo sampling technique and improved quick sort method are used to select the fault states.A series of vulnerabil ity indexes,such as failure probability,absolute power flow betweeness,structure importance factor,probability importance factor and structure probability importance factor are considered.Simulation results show converges speed of the reliability evaluation method is faster than tradition method,and for more factors are considered,it is faster to find the vulnerabilities of system.The application prospect of the method proposed in this paper is widely.