电化学储能参与电网低频第三道防线的控制策略

针对日益凸显的电网频率安全稳定问题,利用电化学储能的快速响应特性和功率双向调节能力,将其纳入到基于就地信号响应的频率安全第三道防线中,应对大功率缺额引起的低频问题。首先,分析电化学储能在低频第三道防线中的功能定位,基于单机带负荷等值模型,提出电化学储能参与频率安全第三道防线的频率响应模型;分析电化学储能分轮次动作的必要性和前提条件,提出临界容量及其计算方法。然后,研究电化学储能低频校正控制策略的制定方法,提出表征频率恢复效果和控制代价的综合指标,计及运行方式和故障场景,建立加权优化模型并整定电化学储能各轮次控制量。最后,实际电网的算例分析表明,所提出的校正控制策略具有较好的频率控制效果和适应性,有助于拓展电化学储能在电网中的应用场景。

A control strategy for the low frequency third defense line of power grid containing the electrochemical energy storage

The problem of frequency security and stability of the power grid has become increasingly prominent. The distributed electrochemical energy storage has the capability of rapid power regulation and can be contained into the third defense line for frequency security based on on-site signal response. Aiming at the low frequency problems caused by high-power shortages, the paper analyzes the function of the electrochemical energy storage in the third defense for frequency security. The frequency response model of the third defense line for frequency is established based on the model of single generator with concentrated load containing the electrochemical energy storage. For the over-control problem that may be caused by the large-scale application of the energy storage, the necessity and conditions of regulation in rounds are analyzed. Furthermore, a tuning method of strategy in rounds for the energy storage to participate in the low-frequency corrective control is proposed, considering multiple operation modes and failure scenarios. The control strategy is tuned based on the comprehensive optimization control objectives of transient frequency, steady-state frequency and control cost. It is verified that the tuned control strategy has good frequency control effect and adaptability based on an actual power grid, which is helpful to expand the application scenarios of the electrochemical energy storage into the power grid.