Impact of off-nominal frequency values on the generation scheduling of small-size power systems

Abstract

This paper studies the impact of off-nominal steady-state frequency values on the generation scheduling of small-size power systems. For that, a security-constrained stochastic unit commitment problem that explicitly considers frequency variations and primary frequency control is proposed. The frequency of the system under normal operating conditions is characterized by a probability distribution that can be estimated from real-world measurements. The reserve scheduling is considered to face uncertain variations of renewable power and demand. A set of contingencies modeling generating unit failures is considered to ensure a N-1 security criterion. Numerical results obtained from a realistic case study show that modeling off-nominal steady-state frequency values in the scheduling model reduces the probability of experiencing high frequency deviations and unserved demand after contingency.