Frequency versus Speed Feedback for Transient Stability Control via Energy Storage

Transient stability is often the limiting factor in power transmission. Due to lack of inertia, high penetration of inverter-based generation may exacerbate such instabilities. Emerging energy storage systems (ESSs) present a unique opportunity for addressing transient stability via real-power modulation. Such control could help avoid instabilities or the need for remedial actions such as load shedding. Some promising ESS transient-stability control strategies proposed in the literature utilize real-time wide-area generator speeds as the fundamental feedback signals. A potential proxy for the generator speed is electrical frequency obtained from a phasor-measurement unit (PMU) incorporated into a wide-area measurement system. This paper examines the impact of using PMU-based frequency measurements for such applications.