This paper presents a security constrained unit commitment (SCUC) with continuous intra-hour time-varying reserves. The hourly formulation extends the power-based UC formulation and has reserves which vary continuously within the hour, as opposed to the traditional hourly energy-based SCUC that uses constant reserves within the hour. We show that the traditional hourly energy-based formulation cannot ensure N-1 security at all times, since this formulation is not able to take the power trajectories of units within the hour into account. This is remedied by an hourly power-based version which allows the formulation of contingency constraints to guarantee N-1 security at all times within the hour. The proposed formulation uses continuous time-varying reserves which lowers the cost for providing reserves and makes better use of units’ flexibility while still ensuring N-1 security. The energy-based and power-based formulations are evaluated using different versions of a 5-min security-constrained economic dispatch (SCED) based on real load data, thus simulating the real time operation of the system under different assumptions for reserve procurement. The results show that the power-based formulation increases security compared to the energy-based formulation, both if reserves are fixed to the values from the SCUC or co-optimized in real time by the SCED.

本文提出了具有连续小时内时变储备的安全约束单位承诺（SCUC）。每小时公式扩展了基于功率的 UC 公式，并且具有在小时内连续变化的储备，而传统的基于小时的 SCUC 在小时内使用恒定储备。我们表明，传统的基于小时能量的公式不能始终确保 N-1 安全，因为该公式无法考虑单元在小时内的功率轨迹。这可以通过基于每小时功率的版本进行补救，该版本允许制定应急约束以保证每小时内的 N-1 安全性。提议的公式使用连续时变储备，这降低了提供储备的成本，更好地利用了单元的灵活性，同时仍确保 N-1 安全。基于实际负载数据，使用不同版本的 5 分钟安全约束经济调度 (SCED) 评估基于能量和基于功率的公式，从而模拟系统在不同假设下的实时运行储备采购。结果表明，与基于能量的公式相比，基于功率的公式提高了安全性，如果储备固定为 SCUC 的值或由 SCED 实时协同优化。基于实际负载数据，使用不同版本的 5 分钟安全约束经济调度 (SCED) 评估基于能量和基于功率的公式，从而模拟系统在不同假设下的实时运行储备采购。结果表明，与基于能量的公式相比，基于功率的公式提高了安全性，如果储备固定为 SCUC 的值或由 SCED 实时协同优化。基于实际负载数据，使用不同版本的 5 分钟安全约束经济调度 (SCED) 评估基于能量和基于功率的公式，从而模拟系统在不同假设下的实时运行储备采购。结果表明，与基于能量的公式相比，基于功率的公式提高了安全性，如果储备固定为 SCUC 的值或由 SCED 实时协同优化。