高比例可再生能源并网的电力系统灵活性评价与平衡机理

Flexibility Evaluation and Supply/Demand Balance Principle of Power System With High-penetration Renewable Electricity

高比例可再生能源并网的电力系统中,波动电源和负荷不确定性双重叠加,采用增加备用应对不确定性的模式在技术和经济上均难以为继,亟待建立一种新的灵活性平衡机制。该文首先给出了电力系统灵活性的概念及其特征,提出了多时间尺度灵活性供给–需求平衡的通用数学方法和灵活性度量指标;建立灵活性裕度的概率模型,阐明曲线平移类、曲线整形类和综合类等3种类型灵活性增加途径;最后,通过我国北方某大型风电基地实际数据,以调峰灵活性为例,对该文提出的平衡机理和指标体系进行了验证和测算。算例表明灵活性指标能够与系统负荷损失风险、新能源限电建立线性关联,依据灵活性平衡机理可实现源–网–荷–储复杂场景下的综合灵活性优化。

With the integration of high shares of variable renewable energy （VRE）, both increasing uncertainty of VRE and load make it difficult to envelope the total uncertainty by increasing reserve in a technical or economic way and urgently request to establish a new flexibility balance rules. This paper proposed the definition of power system flexibility and its characters, then introduced the universal mathematical description of power system multiple time scale flexibility ＂supply/demand＂ balance, also the evaluation indices for it. Based on the flexibility adequacy model, the flexible promotion options were divided into 3 types according to their action mechanism. Finally, case studies based on practical data from one power grid in northern China were conducted to verify the proposed method and indices. The results show that the proposed indices have obvious linear relationship with system security and curtailment so that the balance principle can be applied in the optimal flexibility planning in the complex ＂Generation-Grid-Load-Storage＂ scenario.