Benchmarking and Simulation of Frequency Events in the Eastern Interconnection

This paper presents a frequency response study for the Eastern Interconnection (EI) which was performed in line with NERC Long Term Reliability Assessment. The study included benchmarking actual frequency events recorded in the EI, developing a new 5-year horizon low inertia system model with the future generation resource mix, simulating large resource contingency events, and testing mitigation solutions for frequency criteria violations. As the EI is being integrated with high penetrations of inverter-based resources, the generation resource mix changes significantly and system synchronous inertia decreases, which, along with new or existing resources control capabilities, impacts system frequency response. The purpose of this study was to ensure that the EI would have sufficient frequency support over the next 5 years with the future generation resource mix, system synchronous inertia, load and interchange levels and governor participation, and the system frequency does not reach Under-Frequency Load Shedding (UFLS) levels for large unplanned generation outages. This paper also discusses new automation tools developed for the study, and the methodology, models and criteria used in the study¹¹The Eastern Interconnection Planning Collaborative (EIPC) represents a coalition of regional Planning Coordinators in the Eastern Interconnection (EI), performs technical studies of transmission planning, and assesses the impacts on various energy policy options for the grid determined to be of interest by state, provincial, and federal policy makers and other stakeholders in collaboration with their respective NERC Planning Authorities..