| The physical nature of network topology determines its functional characteristics,which has a profound impact on its stable operation,security and reliability.The large power outage accidents in the power grid are caused by the failure of fragile components in the topology,which leads to the cascading failure spreading in the topology,Therefore,it is of great significance to grasp the topology structure and evolution rules of power grid to effectively prevent chain faults and improve the safety performance of power grid.In this paper,the evolution model of the power grid is studied based on the complex network theory and the voltage level and partition characteristics of the power grid planning and design,including the following work:(1)In order to analyze the topological characteristics of the actual power grid,a complex network topological model and a network topological vulnerability assessment method considering the voltage level are proposed.By using the complex network theory,the topological overall modeling of the actual power grid is carried out,and the layered modeling of the power grid structure of different voltage levels is carried out.The statistical characteristics of complex networks with different voltage level network topologies are revealed.Based on the influence of voltage level and node power on node importance,a comprehensive vulnerability index of network topology and electrical characteristics considering voltage level factor is proposed.Simulation of the IEEE-118 node system shows that the comprehensive importance index considering the electrical performance of the voltage level factor can better reflect the topology performance of the grid.it shows the necessity of considering node voltage levels in complex networks and lays a foundation for establishing the local world evolution model considering different voltage levels.(2)A local world evolution model considering different voltage levels and high-voltage direct current transmission and distributed generation is proposed.The model is based on the actual grid evolution mechanism.Considering the high-voltage,medium-voltage and low-voltage grids,the number of grid nodes connected to the grid and the connection methods are different,and the characteristics of local growth of the grid are considered.By simulating the model and comparing it with the US Western Power Grid and China Southern Power Grid data simulation,the proposed model is closer to the evolution law of the real grid than the traditional evolution model,which is beneficial to the overall dynamic evolution of the grid and the natureof the grid structure.Analysis of the occurrence of grid cascading failures,At the same time,considering the high-voltage direct current transmission and distributed generation,the grid topology evolution model is established,The result has a larger average path length and a smaller clustering coefficient than the actual grid,which will reduce the probability of large-scale power outage and provide reference for future grid structure planning.(3)This paper proposes a hierarchical partition evolution model based on multi-community partition and voltage level hierarchy.Firstly,the grid topological community partition model based on electrical median GN(Givern-Newman)splitting algorithm is established.The performance of the grid community division scheme is evaluated by the weighted network modular Q function,and the grid community division scheme is selected.Then,based on the community classification method and the voltage level stratification characteristics,the multi-community partition and voltage level stratification network evolution model is established.The comparison of the local world evolution model without considering the partition characteristics proves that the model can be more consistent with the evolution law of the actual power grid in the degree distribution,average shortest path and other characteristic parameters. |
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