考虑短期波动与弃电风险的水光互补系统中长期双层嵌套优化调度

Medium-and Long-Term Double-Layer Nested Optimal Scheduling of Hydro-PV Complementary System Considering Short-Term Power Fluctuation and Curtailment Risk

由于中长期调度对短期水电调节能力与光电随机波动性考虑不足,不利于高比例新能源渗透下水光互补系统长期消纳与短期并网的有效承接。该文提出统筹中长期消纳电量效益与短期波动、弃电风险的调度方案,构建外层月度库容决策搜索与内层短期水光互补策略相耦合的双层嵌套调度模型与求解方法。首先,从出力形状、电量角度分析光电波动幅度与水电调节能力的互补关系;然后,制定基于电量区域标识和波动平抑方法的短期水光互补策略;接着,引入水光消纳矢量关系加速模型求解;最后,通过模拟水光场景与选取波动参数确定边界,结合目标函数建立风险与效益方案集。实例研究表明:波动参数与发电并网质量具有良好的适配性,对互补系统调度决策影响显著;波动与弃电风险控制能够有效兼顾能源消纳电量与电力系统平稳运行;方案集提供了不确定性场景、波动参数向量集下的决策具象化平台,所呈现的电量效益与波动风险偏好信息能够为互补系统与电力系统的协调运行提供应用指导。

The hydropower(Hydro)and photovoltaic(PV)power complementary system is unified operation through the control center.It contributes to promote the integration of renewable energy and power system.However,the risk of energy loss and transmission power fluctuation will be induced when the Hydro-PV power exceeds the regulation range of the power system.Traditional medium-and long-term scheduling model of Hydro-PV complementary system does not consider short-term Hydro regulation ability and PV random fluctuation.Therefore,the operating rules formulated by such model are difficult to effectively guarantee stable operation of the power system under a state of new energy high proportion penetration.In addition,it’s not conducive to coordinate long-term operation benefits and short-term power grid connection risks.To address these issues,this paper proposes a medium-and long-term double-layer nested scheduling model and solution method considering short-term power fluctuation and curtailment risk.It aims to optimize the decision of medium-and long-term scheduling and guarantee the quality of short-term power generation.Firstly,a complementary relationship between PV fluctuation and Hydro regulation ability was proposed form the perspective of power shape and quantity.Secondly,the point to improve the quality of grid connection was to reduce the risk of power fluctuation and curtailment.And on this basis,a short-term Hydro-PV complementation strategy based on the fluctuation parameters(,SΔRΔ)and fluctuation damping method was proposed.This way could optimize the short-term generation plan and identify the benefit(power accommodation)and risk(power fluctuation and curtailment)information.Thirdly,a two-layer nested scheduling model and solution method coupling the outer monthly reservoir capacity decision search with the inner short-term Hydro-PV complementary strategy was developed.Then,a Hydro-PV complementary vector relation and particle swarm optimization(PSO)were introduced to improve the model solving efficiency.Finally,the decision boundary was determined by Hydro-PV scenarios simulation and fluctuation parameters selection,then the risk and benefit scheme set and scheduling decision platform were established by combining the objective preference.The results show that energy loss risk control can avoid power curtailment during operation cycle.Meanwhile,the fluctuation risk control improves the short-term power grid-connected quality.When SΔ=0,the PV power is fully compensated and then the system power meets the transmission form of subsection stability,which can effectively reduce the operating pressure of the power system.The decision platform shows that the benefit of storage capacity rising will be gradually damaged with the increase of risk control requirements.In this process,the increase of fluctuation parameters can improve the power grid-connected quality at the expense of power accommodation benefit.This indicates that the accuracy of scenarios prediction and the rationality of fluctuation parameters selection are conducive to coordinate the relationship between benefit optimization and risk aversion.The following conclusions can be drawn from the simulation analysis:(1)The proposed Hydro-PV complementary relationship reveals the effect of fluctuation risk control is positively correlated with the balance power that Hydro can call,but if the balance power exceeds the capacity boundary of transmission channel,the risk of power abandonment will be caused.(2)The proposed short-term Hydro-PV complementary strategy can guarantee the complementary system power as close as possible to the transmission form of subsection stability.(3)The proposed double-layer nested optimization framework can effectively regulate risk and benefit elements at different time scales.It provides a decision platform for Hydro-PV complementary system,which can support administrator to select a reasonable scheduling scheme quickly,and then fully coordinate the energy utilization efficiency with the power grid connection process.