Security constrained unit commitment with continuous time-varying reserves
article
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 powerbased 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.
Topics
TNO Identifier
957240
Source
Electric Power Systems Research, 199
Collation
11 p.