Research On Transmission Network Planning Strategy Considering Long-Range Dependence Risk

With the gradual expansion of the power system,transmission network planning has become increasingly complex.In order to ensure the safe and stable operation of the system,any risk that may cause a blackout cannot be ignored.Based on the self-organized critical theory,this paper proposes a transmission network planning strategy to eliminate long-range associated risks in view of the shortcomings of the current power system in the transmission network planning without considering the long-range associated risks of the system.In the planning stage,the system risk level is reduced through a reasonable planning strategy,and the strength of the power grid is improved to prevent the occurrence of blackouts.Firstly,the paper introduces the research status of self-organized critical theory and transmission network risk planning in power system,and clarifies the content and significance.Secondly,based on the fractal method,the time series long-term memory model method ARFIMA(p,d,q)and wavelet variance,the long-term memory characteristics of the historical power outage data time series of two power systems in Bolivia and China,ie Long-Range Dependence,LRD conducts empirical research.Then,it analyzes the application of Hurst index in power system and its significance for power grid planning,and expounds the relationship between Hurst index and transmission capacity margin and system risk,and clarifies the significance of its analysis system long-range associated risk.Thirdly,the application of Hurst index in power system and its significance for power grid planning are analyzed,and the relationship between Hurst index and transmission capacity margin and system risk are expounded.The significance of using Hurst index to analysis system LRD risk is clarified.Fourthly,based on the general model of transmission network planning,the economic optimal objective function is established,and an evaluation index system that comprehensively considers the system LRD risk and balance of load is proposed.Finally,two planning strategies for suppressing LRD risk are proposed: pre-planning and incremental planning.According to the relationship between the expansion capacity of the transmission system and the risk,the pre-planning time is determined.The improved OPA model was used in the analysis of the example to simulate the IEEE-30,IEEE-57,and IEEE-118 systems.The relationship between LRD sequence and random sequence,the influence of pre-planning and incremental planning on system H-value,LRD risk and system entropy are analyzed.The simulation results show that the proposed strategies can effectively reduce the LRD risk and optimize load distribution.In view of the practical application of the model,four historical data reorganization schemes are proposed.The simulation results verify that the proposed planning strategy can reduce the system LRD risk in the planning stage and reduce the inherent risk level of the system,which is of great significance to improve the robustness and operational safety of system.