| In recent years,power system accidents caused by extreme natural disasters have occurred frequently,causing serious damage to the power grid,resulting in huge losses in the national economy,and also causing great inconvenience to residents’ lives.Therefore,it is necessary to build a core backbone network and improve the critical line fortification standards to improve the ability of the power grid to resist disasters and reduce the losses caused by natural disasters to the power system and society.Based on the new requirements of grid differential planning,this paper conducts in-depth research on four aspects of grid vulnerability component assessment,differential economic assessment,core backbone grid construction,and key line differentiation enhancement,and proposes a disaster-resistant grid differential planning model considering with regional meteorological factor.The main research results are as follows:(1)According to the selection principle of the disaster-resistant backbone network,a comprehensive evaluation index system for grid vulnerability components was constructed.Meanwhile a comprehensive evaluation method based on anti-entropy method-AHP quadratic programming combined weighting is proposed to evaluate the component fragility,so that the key lines and nodes in the system are obtained,which provides a basis for the construction of the subsequent backbone network.(2)Combining the extreme value I theory and the deformation index when the line is subjected to stress,this paper establish a comprehensive failure rate model of the line at a specific wind speed in the region,and calculate the differential impairment “benefit” in the whole life cycle of the line through the comprehensive failure rate.On this basis,a differentiated economic evaluation system is established,and a segmentation assessment method is proposed for different meteorological regional lines,which more accurately calculates the disaster prevention benefits of the line differential transformation,and strengthens the differentiation of key lines for subsequent determination.The grade provides a scientific and reasonable economic evaluation standard.(3)A multi-objective bilevel programming model for the differential reconstruction of the disaster-resistant backbone network is proposed.The upper-level planning is based on the economic optimization,the highest load guarantee rate,and the maximum coverage of vulnerable components of the grid as the objective function to construct the core backbone network of the power grid.The lower-level planning model aims at minimizing the total expenditure of line transformation,and generates a differentiated transformation level scheme based on comprehensive failure rate and economic evaluation.The method better balances the economics and reliability of the grid construction,and effectively quantifies the line disaster strengthening level.(4)An NSGA-II algorithm with embedded genetic diagnosis operation is proposed to solve the multi-objective bilevel programming model.The graph-based repair strategy is used to connect the “island” fixing the infeasible solution into a feasible solution,thus improving the convergence of the algorithm.speed.The Nash equilibrium is introduced to obtain the optimal compromise solution,which better balances the benefits between multiple objective functions.The method proposed in this paper is verified by IEEE-39 node.The simulation results show that the core backbone network and the key line differentiation enhancement scheme obtained by the method proposed in this paper can maximize the disaster resistance performance of the power grid under limited investment and ensure the power supply safety of important loads in the event of extreme natural disasters.Provides scientific guidance for differential planning of the grid. |
