Frequency control challenges and potential countermeasures in future low-inertia power systems: A review

Due to the prolific integration of Renewable Energy Sources (RES) worldwide, power system dynamics have been altered extensively. Conventionally, the rotating mass of the Synchronous Generators (SGs) used to supply the stored kinetic energy following a generation deficit. However, because of widespread installation of RES, these conventional SGs are being displaced. As the RES do not necessarily contribute to system inertia without additional control loops, the inertia of the overall system is becoming insignificant. These low-inertia power systems are much more vulnerable to various disturbances and uncertainties associated with modern power grids. As such, low-inertia grids are suffering from challenges such as higher rate of change of frequency (ROCOF), larger frequency deviation, distributed PV trip, distributed generator trip and so on. To counter these new challenges, hidden inertia emulation, synthetic inertia utilization and emulated inertia from various sources are being suggested in recent literatures. This paper intends to present a detailed discussion on power system frequency control challenges in RES dominated grids. In addition, a comprehensive review of possible countermeasures for frequency control in low-inertia power systems from generation and transmission perspectives and future research scopes are discussed in this paper.