A general-order system frequency response model incorporating load shedding: analytic modeling and applications

Recent works have shown that the aggregate load-frequency behavior following a contingency in isolated power systems can be represented by system frequency response (SFR) models. In this paper, an analytic SFR model incorporating an under-frequency load-shedding (UFLS) scheme is presented. The main motivation is to derive closed-form expressions of the load-frequency response that include the effect of the UFLS so that the system and UFLS performance indicators can be directly computed. Consequently, these indicators could then be efficiently used in various new optimization applications involving the SFR-UFLS model. Time-domain simulations with the full-scale power system that the SFR-UFLS model represents also showed that the results agree with those predicted analytically.