Coordinated Planning And Control Strategy Of Power System Considering High Proportion Of Renewable Energy Consumption

The global energy consumption profile is undergoing fundamental changes to meet the electricity demand and to address environmental climate change.Various energy development policies have been formulated by countries all over the world.These strategic objectives aim to increase the penetration rate of renewable energy and reduce the dependence on traditional energy.With the rapid development of renewable energy technology,high penetration of renewable energy power system will become the future development trend.The inherent stochastic and variable nature of renewable energy makes planning and control of power systems a serious challenge.Traditional power system planning aims to determine the timing,location,and size of generation and transmission line expansions during a period to meet predetermined economic and security requirements.Large-scale renewable energy integration leads to gradually increasing uncertainty in the power system,and deviations of renewable energy generation forecasts(too much or not enough)will increase the difficulty of real-time balancing.How to transition a traditional power system to a high penetration renewable energy system? How to formulate the optimal control strategy to realize the economic and secure operation of the new generation power system? Therefore,exploring the research of power system planning and control strategies for high penetration renewable energy accommodation has become an urgent problem in the current power industry.The research work of this thesis includes the following aspects:1)The characteristics and driving measures of a high penetration renewable energy system are analyzed.Based on the analysis of the opportunities and challenges of renewable energy development,the main characteristics of power system with a high penetration of renewable energy are summarized from the aspects of energy consumption,policy environment,technical level,supply and demand balance.This paper puts forward the measures of financial incentive,portfolio standards,market mechanisms,and coordinated planning for renewable energy development.Financial incentives and portfolio standards create a good policy environment for renewable energy.The market mechanism can improve the efficiency of resource allocation and market economy.Coordinated planning and operation control is the key technology to achieve a high proportion of renewable energy power systems.This paper emphasizes the importance of policy incentives,market-driven,and resource complementary to the high penetration of renewable energy systems.2)A coordinated planning model for renewable energy and energy storage considering financial incentives is proposed.In the early stages of renewable energy development,studying the drivers of policy incentives and market mechanisms for the construction of high penetration renewable energy systems can help drive electricity market reforms and achieve strategic energy targets.The generation-side energy storage can smooth the power of renewable energy.The development mode of combining renewable energy and energy storage is of great significance to improve the system economy.Since investors tend to maximize social welfare in regulated electricity markets and aim to maximize profits in liberalized electricity markets.Therefore,the coordinated planning model in regulated and liberalized mechanisms is established respectively.The model can simulate the clearing process of the energy and reserve market in each representative day.The results show that the profit on an investment of renewable energy and energy storage is non-positive in regulated markets,while their profits are non-negative in the liberalized market.Financial incentives are vulnerable and may increase renewable energy curtailment.3)A coordinated planning model of renewable energy,transmission line,and energy storage is proposed to realize renewable energy targets.With the development of renewable energy technology,the penetration rate of renewable energy in power systems increases gradually.A coordinated planning model based on two-stage robust optimization theory is established to achieve the predetermined renewable energy target.Data-driven technology is used to construct multiple flexible uncertain sets to reduce the conservatism of the decision-making scheme.This intractable min-max-min optimization problem is recast as bi-level programming by strong duality theory and disjunctive inequality.The optimal sitting and sizing of renewable energy and energy storage,as well as optimal expansion scheme for the transmission line,are obtained by parallel column and constraint generation algorithm.The example results show that the coordinated planning scheme based on two-stage robust optimization can achieve the trade-off between economy and conservatism.4)A coordinated planning model of renewable energy,transmission line,and energy storage is proposed based on Stackeberg game theory.Large-scale renewable energy integration into the power system will increase the risk of transmission congestion.Achieving the generation targets of higher penetration of renewable energy requires a high capital burden.With the liberalization of the electricity market,social planners hope that merchant investors will participate in the expansion projects of the transmission line to alleviate the investment cost of transmission service providers.Considering the game strategy of merchant investors and social planners,a coordinated planning model of renewable energy,transmission network,and energy storage with a tri-level optimization structure is established.From the perspective of merchant investors,joint investment in transmission lines and energy storage to maximize profit.From the perspective of social planners,joint investment in renewable energy and energy storage to maximize social welfare.From the perspective of system operators,the energy and reserve markets are jointly cleared to ensure the economic operation of the power system.Scenario-based stochastic programming is used to handle the uncertainty of renewable energy and energy storage to trade off the calculation burden and the accuracy of the solution.The results show that the proposed model can obtain the optimal equilibrium solution of merchant investors and social planners.5)The control strategy and evaluation method of power systems for renewable energy accommodation are proposed.The renewable energy accommodation space is determined by the planning scheme,while the actual power generation is determined by the control strategy of the power system.A rolling scheduling model considering renewable energy and load uncertainty is proposed by stochastic model predictive control theory.Then,generalized renewable energy accommodated limit assessment model is established by two-stage robust optimization theory.Renewable energy accommodated limit has the function of dispatching early warning,which can assist the real-time dispatching decision of power system.The results show that the rolling scheduling strategy using stochastic model predictive control is economical and robust.