风电爬坡事件对系统运行充裕性的影响评估

风电爬坡事件具有大波动性和强不确定性的特点,可造成系统中发用电的严重不平衡,从而导致负荷损失。在分析风电爬坡事件特征和爬坡预测研究现状的基础上,建立了风电爬坡事件模型,定量表示爬坡事件表征量与风电功率曲线之间的关系;同时考虑负荷预测的不确定性,采用场景削减方法生成风电爬坡过程对应的典型净负荷场景集。构建了评估系统运行充裕性的指标体系,推导了缓冲失负荷概率指标的计算公式;将系统状态分为充裕、失负荷和临界3种,分别计算各状态对应概率及失负荷严重程度。以甘肃电网为例,典型事件的评估结果验证了所述方法和指标体系的有效性和合理性,分析了常规机组爬坡速率及系统备用比例在防范风电爬坡事件不利影响方面的作用。

Assessing Impact of Wind Power Ramp Events on Operation Adequacy of Power Systems

Due to the characteristics of large volatility and strong uncertainty, wind power ramp events(WPREs)are likely to cause the active power imbalances of power systems and even load loss accidents. Based on the analysis on characteristics and prediction status of WPREs, a WPREs model is proposed to establish the quantitative relationship between charactering quantities and wind power curves. The uncertainties of WPREs and load forecasting are simultaneously considered, and the scenario reduction method is used to generate the typical scenarios set of net load during WPREs. With the derivation of mathematical calculating method of buffered load loss probability based on scenario reduction, an indicator system is established, by which the system status can be categorized as being adequacy, load loss and marginal, and the corresponding probability of each status and severity of load loss can be calculated respectively. The assessment results of typical events based on the Gansu power grid verify the effectiveness and rationality of the proposed assessment method and indicator system. The roles of ramp rate of conventional units and proportion of reserve capacity in preventing the adverse effects of WPRE are further analyzed. This work is supported by National Basic Research Program of China(973 Program)(No. 2012CB215101).