Primary frequency control techniques for large-scale PV-integrated power systems: A review

The increasing amount of solar photovoltaic (PV) penetration substitutes a large portion of conventional synchronous power plants. During the peak power production period, it may lead to reduced the rotational inertia and thereby deteriorate inherent inertial response of the power system. It is assumed that the conventional generators mainly provide the necessary frequency regulation service. Conversely most of the PV inverters are designed to operate in the maximum power point (MPP) to generate the maximum revenue. Due to the synchronization mechanism, an inherent close coupling exists between the speed of the conventional generator and the grid frequency. On the contrary, the inverter interface completely decouples PV from the grid. As a result, PV systems do not inherently contribute to the system inertia. Therefore, it is important to investigate the impact of reduced inertia on stability, control and operation of a power system. This paper presents an extensive review of research related to the main power system operational challenges with respect to the massive deployment of PV sources. Besides, this paper aims to provide a comprehensive review of various control approaches and applications of battery energy storage system (BESS) to improve the inertial response of a low-inertia power system.