Research On The Unit Commitment Strategy In The Interconnected Power Grid With Wind Power Based On Multi-scenarios Risk Analysis

The research topic of this paper comes from Youth Fund of the National Natural Science Foundation of China “Power-Gas” integrated energy system coupling risk assessment theory research based on serious fault set screening technology(No.51807129)” and State Grid Shanxi Electric Power Company Research Program “Study on stability characteristic change and control strategy of shanxi power grid under uhv backbone network — new energy and cross-region power grid optimization strategy(No.52053017000T)”.Development of renewable energy sources such as wind power generation technology is a response to the global climate environment degradation and a forceful measures to the problems of the energy scarcity such as coal,fossil,and can effectively promote the global energy structure adjustment and the low carbon transition of energy consumption.Ensuring the consumption of renewable energy is the basic requirement for the quality and efficient development of its related industries.In recent years,China has attached great importance to the absorption of new energy.The “Clean energy absorption action plan”proposed by the national development and reform commission and the energy administration points out that the absorption of clean energy in China will be basically solved by 2020.In view of the regional distribution differences of wind power and load in China,State Grid Dispatching Center issued the“trans-regional and inter-provincial surplus renewable energy power spot pilot rules(trial)” in 2017 to promote the cross-regional consumption of new energy.Due to the low prediction accuracy,anti-peak adjustment and uncontrollability of wind power,large-scale wind power integration into the power grid brings more uncertainty to the operation of the power system.Power grid interconnection can weaken the impact of wind power uncertainty on power grid operation to some extent,but at the same time it increases the complexity of unit commitment problem.Based on the above background,There is an urgent need to conduct research on the unit commitment of interconnected power grid with large-scale wind power that take operational risk factors into account.In order to obtain a practical and feasible unit commitment scheme in a limited computing time,it is necessary to fully consider the operational characteristics of the interconnected grid and screen typical scenarios to measure the grid operation risk.This paper proposes a method for constructing an interconnected grid uncertainty scene set.The risk quantification index that the expected wind power curtailed(EWPC)and the expected energy not supplied(EENS)of interconnected power grid are introduced into the objective function in the form of a penalty function.Taking into account the network security operation of the interconnected grid,inter-regional standby coordination,and the operating characteristics of the unit,a multi-area interconnected grid safety constraint unit commitment model that takes into account the multi-scenario operation risk is established.The centralized optimization scheduling strategy is adopted to realize the coordinated optimization of the interconnection grid power generation-backup in space and time.The correctness and effectiveness of the unit commitment strategy are verified by the two-zone 12-node system.With the expansion of power grid interconnection,still adopt the centralized optimization scheduling strategy may made the calculation efficiency decreases obviously,because the optimization model is too complex,the number of decision variables increases dramatically,the computational memory is insufficient,transmission information between regions is difficult and other bottlenecks.This paper proposes a decentralized coordinated optimal scheduling strategy for unit commitment with wind power.Based on the target cascading technology,the unit commitment model of the multi-region interconnected power grid is divided into two layers.The upper coordinator optimizes the voltage phase angle of the boundary nodes of each region,and the lower layer optimization is to solve the security constrained unit commitment problem of their respective regions in a parallel way,and sets the EWPC and EENS limits in the unit commitment model of each region to quantify the operational risks of each area to ensure the operational reliability requirements of the grid.The whole problem is solved by alternating iterative solution of the upper and lower coordination and optimization problems,so as to realize the coordinated optimization of the internal unit shutdown schedule,standby plan and tie line transmission power.Finally,the decentralized coordination optimization strategy is used in the 2-zone 12-node system and the IEEE RTS96three-area interconnected system to verify the effectiveness of the optimization strategy.