A frequency based short-term reliability index considering feedback control constraints and renewable energy source incorporation

In this work, we provide a new short-term reliability index that accounts for practical grid properties. The proposed index addresses the system frequency reliability and controllability of the grid and its deviation over a short time period. In the formulation, demand, renewable source, battery and generators are incorporated in stochastic manner. Using the equilibrium of demand and supply, and the physical constraints of automatic generation control (AGC), a model is developed, from which the system frequency distribution is obtained. From the contrived system frequency statistical function, referred to as Frequency Reliability Distribution Function (FRDF), various criteria can be developed for short-term reliability. The developed FRDF along with the pertaining metrics are utilized for some case studies with IEEE reliability test system.