Optimal generation mix for frequency response adequacy in future power system

Abstract

• Propose a novel exposition of optimal generation mix. • Assess PFR adequacy with diversified generation mix. • Model RES uncertainty with pragmatic characterization in the generation mix optimization problem. • Analyse overall cost for different generation mix cases. Strict enforcement of government policies to integrate high generation share from renewable energy sources (RES) like wind and PV would create inevitable operational challenges for the utilities to deliver Frequency Response (FR) services. Uncertain RES generation characteristics would worsen the situation for SO, to detain initial frequency deviation following the largest generation outage. This necessitates investigation of optimal generator combination for securing PFR adequacy with simultaneous characterization of uncertainty. In this regard, this paper proposes a novel Modified Interval (MI) based optimal generation mix formulation for operation cost minimization and FR adequacy. RES uncertainty is characterised by forecasted upper and lower bound, while hourly ramp needs are based on the net load scenarios. Proposed model is assessed on one area IEEE reliability test system. Rate of change of frequency (ROCOF) and frequency deviation are considered as network security limits to obtain optimal generation mix. Results obtained provide, overall cost performance, PFR and optimal generation mix, without violating system security criteria. This model would certainly assist SO, to enhance system's inertia and PFR adequacy at short-term system operations and could be extended for long-term planning framework.