基于两阶段随机优化建模的新能源电网灵活性资源边际成本构成的机理分析

针对大规模可再生能源并网给电力系统安全稳定运行造成的影响,考虑纳入燃气轮机储能等灵活性资源共同调节风电的波动性,构建了机组出力和备用容量联合优化的两阶段发电调度随机规划模型,并计及常规火电机组的多运行状态约束。然后,以模型中两阶段功率平衡约束对应的拉格朗日乘子分别作为日前和实时电价,从模型角度探究了边际成本构成机理。从灵活性资源供应的紧缺程度和灵活性资源需求的旺盛程度两个方面剖析灵活性资源的供需匹配对于系统边际电价的深层影响机理。算例结果说明了灵活性资源在应对风电不确定性和抑制尖峰电价的有效性,同时说明了多时间尺度的爬坡约束耦合、日前备用与实时出力调整量的耦合对于系统边际电价的影响。

Mechanism Analysis of Flexible Resources’Marginal Price in New Energy Grid Based on Two-stage Stochastic Optimization Modeling

Due to the impact of the large-scale renewable energy on the safe and stable operation of power system,the flexible resources such as gas turbine and storage are considered to adjust the volatility of the wind power.A two-stage stochastic scheduling model co-optimizing energy and reserve was established,with constraints describing multi-operating states of conventional thermal power units.Then,the Lagrange multipliers corresponding to the two-stage power balancing constraints in the model were taken as the day-ahead and real-time electricity prices,respectively,and the mechanism of marginal cost from the perspective of model was explored.The influence mechanism of flexible resources on system marginal price was analyzed in depth from two aspects:the lacking degree and exuberant degree of demand for flexible resources.Case study illustrates the effectiveness of flexible resources in dealing with the uncertainty of wind power and restraining peak price.Moreover,the influence of coupling of multi-time scale climbing constraints and coupling of day-ahead reserve and real-time output adjustment on system marginal electricity price was analyzed.