计及灵活性承载度的电网评估与扩展规划方法

灵活性评估与规划已成为含高比例可再生能源电力系统运行的核心和关键。现有灵活性研究主要集中于灵活性供需匹配层面,忽略了电网线路传输承载能力对灵活性供需传输的影响。鉴于此,首先,分析线路层面的灵活性供需传输过程,建立电力系统灵活性供需传输模型。然后,提出灵活性承载度概念及度量指标。在此基础上,提出计及灵活性承载度的供需平衡评估方法,可阐明电网灵活性缺额成因,辨识系统薄弱环节。最后,提出基于灵活性评估的输电网两阶段扩展规划方法,并利用Garver-18节点系统验证有效性与合理性。算例表明:一方面,灵活性承载度指标可量化电网对灵活性供需的传输承载能力,更加符合电力系统实际;另一方面,所提规划方法可挖掘线路输送潜力,扩展线路灵活运行空间,有效提升电力系统灵活性。

Evaluation and expansion planning method of a power system considering flexible carrying capacity

Flexibility assessment and planning have become the core and key of a power system which has a high proportion of renewable energy.The existing research on flexibility mainly focuses on the matching level of flexible supply and demand,which ignores the impact of line carrying capacity on flexible supply and the demand transmission process.In view of this,first,a flexible supply and demand transmission model of a power system is established by analyzing the transmission process of flexibility at the line level.Then,the concept and measurement index of flexible carrying capacity are proposed.On this basis,the evaluation method of supply and demand balance considering flexible carrying capacity is proposed.The analysis of the causes of the lack of flexibility and identification of the weak links of the system can be handled through this method.Finally,a two-stage expansion planning method based on flexibility assessment is proposed,and the validity and rationality of the method are verified by using the Garver-18 node system.The example shows that on the one hand,the flexible carrying capacity index can quantify the transmission capacity of power grid.This is more in line with the actual situation of power system.On the other hand,the proposed method can tap the potential of transmission lines,expand the flexible operation space of grid structure,and effectively improve the flexibility of the power system.