基于形态学分解的大规模风光并网电力系统多时间尺度灵活性评估

Multi-scale Flexibility Evaluation of Large-scale Hybrid Wind and Solar Grid-connected Power System Based on Multi-scale Morphology

大量以风电和光伏为代表的间歇性可再生能源的接入对系统可控电源的灵活运行能力提出了更高的要求,为实现含高比例可再生能源的电力系统可靠性运行,亟需建立一套考虑风光出力特性的系统灵活性定量评估体系。考虑新能源发电的多时间尺度波动特性,提出一种基于形态学分解的电力系统灵活性评估指标及其计算方法。首先通过数学形态学算法分解净负荷曲线,得到多时间尺度分量曲线,并根据不同频段的波动分量得出对应的向上、向下灵活性需求;然后,建立系统内不同类型可控机组在不同波动时间尺度下的灵活性调节能力模型;通过对同一时间尺度下的灵活性资源与需求的匹配分析,计算各时间尺度的向上、向下灵活性不足概率、灵活性不足期望和灵活性裕度期望指标;加权形成系统灵活性评估综合指标。基于南方某电网实际数据进行系统灵活性指标评估,验证所提指标和评估方法的有效性。

Development of renewable energy puts forward higher requirements for flexible operation capability of controllable power balance. In order to realize reliable operation of power system with high proportion of renewable energy, it is urgent to establish a quantitative index system and an algorithm for evaluating power system flexibility considering characteristics of wind and solar output. In this paper, considering multi-time-scale characteristics of renewable generation, a set of flexibility evaluation indices and its calculation method based on morphological decomposition were proposed. Firstly, the multi-time-scale components of net load curve were decomposed with mathematical morphology algorithm, and corresponding upward and downward flexibility requirements were obtained according to fluctuated components. Then, an adjustment capability model for different types of controllable units at different time scales was established. Through comparison of flexible resources and requirements, the upward and downward flexibility deficiency probability, flexibility deficiency and margin expectation indicators at each time scale were calculated. In turn, it could be weighted to form a comprehensive indicator of system flexibility evaluation. Evaluation of system flexibility indicators based on the data from an actual grid in South Chinaverifies effectiveness of the indicators and evaluation methods.