Operational flexibility is required in power systems to mitigate load-generation imbalances. Inflexibility either results in infeasible scheduling or shift resources from their economic operating point. System operators must estimate flexibility requirement, assess its availability from committed resources, and take corrective measures to handle upcoming inflexibility events. Various metrics are integrated with economic dispatch to quantify different facets of flexibility — ramp, power, and energy. Consideration of all three facets is essential for its adequate assessment, but is often neglected in literature and requires an in-depth investigation. Further, existing literature hardly consider resources’ day-ahead scheduling decisions while evaluating flexibility for real-time operations. This results in erratic assessment of available flexibility. In this context, the paper proposes a comprehensive metric to quantify flexibility in terms of ramp, power, and energy insufficiency by simultaneously considering their system-wide requirement and availability. A Resource Flexibility Index based on operating range and ramping capability of resources is proposed for accurate indication of available flexibility. The proposed metric is integrated with real-time stochastic multi-interval scheduling framework that considers day-ahead operational constraints. Netload forecast and associated uncertainty are characterized using Long Short-Term Memory and Markov Chain Monte Carlo techniques. Results highlight that the flexibility index is proportional to system’s netload variability handling capability and average inflexibility can be reduced up to 97% with the utilization of emerging resources and ramp products. The proposed tools are of value to power system planners and operators to manage netload intermittency.

电力系统需要运行灵活性来减轻负载生成的不平衡。不灵活要么导致不可行的调度，要么将资源从其经济运行点转移。系统操作员必须估计灵活性要求，评估其从承诺资源中的可用性，并采取纠正措施来处理即将发生的不灵活事件。各种指标与经济调度相结合，以量化灵活性的不同方面——斜坡、功率和能源。考虑所有三个方面对于充分评估至关重要，但在文献中经常被忽视，需要深入调查。此外，现有文献在评估实时操作的灵活性时几乎不考虑资源的日前调度决策。这导致对可用灵活性的不稳定评估。在这种情况下，本文提出了一个综合指标，通过同时考虑系统范围的要求和可用性来量化斜坡、功率和能源不足方面的灵活性。提出了基于操作范围和资源爬坡能力的资源灵活性指数，以准确指示可用灵活性。所提出的指标与考虑日前操作约束的实时随机多间隔调度框架相结合。使用长短期记忆和马尔可夫链蒙特卡罗技术表征净负载预测和相关的不确定性。结果突出显示，灵活性指数与系统的净负载变化处理能力成正比，并且随着新兴资源和斜坡产品的利用，平均不灵活性可以降低高达 97%。提议的工具对电力系统规划人员和运营商管理网络负载间歇性很有价值。