The Estimation Of Nodal Power Supply Capability Of Transmission System Through Network Connectivity

Key infrastructure is the core of a country and the material condition for human survival and development.As an important component and functional core of key infrastructure,power system plays an important role in reliable operation.However,since 2003,there have been a number of large-scale power outages in various countries,resulting in serious losses.Although they are relatively rare events,their effects can be catastrophic.In the future,when the power system is marketized and new energy is continuously connected to the large power grid,the operating pressure and challenges faced by the power grid will inevitably increase.Therefore,in order to avoid the serious consequences of large-scale power failure,it is bound to further carry out the early warning study of cascading failure.The traditional reliability research method looks at the problem from the perspective of system to component.Due to the heterogeneity of resource distribution,it is difficult to estimate the scale of power failure accurately.If we evaluate the power supply reliability of each node separately from the perspective of each load node,then the power failure risk of the whole system can be decomposed into the evaluation of local system,which can effectively avoid falling due to system scale increase calculation efficiency and greatly improve the real-time performance of the evaluation method.Based on this idea,the following contents are studied in this paper:1)The shortest path search algorithm and the power flow tracking algorithm will be adopted to analyze the power supply path and power supply ratio of generator nodes to load nodes in the calculation examples of different scales.2)This paper will propose the definition method of node connectivity index.The node connectivity index is calculated only by the topological information of the system,the line power flow,and the local load information without model-based power flow calculations.3)In this paper,IEEE-118 bus test system is taken as an example,and the conventional optimization power flow is used as a comparative analysis tool to verify the corresponding relationship between node connectivity and node proportional load loss of each load node under different load levels and under different failure conditions.The reliability model of different load nodes and the connectivity threshold of nodes are analyzed.