WAMS-based frequency regulation strategy for photovoltaic system in isolated power systems

Maintaining frequency stability is a necessity for an isolated power system. The frequency regulation participation of photovoltaic generation system (PVs) is vital for an isolated power system with large scale PVs penetration, especially when the frequency regulation capacity of the isolated power system is limited. The deloaded operation for PVs can provide supplemental primary frequency regulation capacity. With a high value of deload margin, PVs have a higher capacity for frequency regulation, but this may result in economic loss. Hence, there should be a tradeoff between the economic effect and the capability for frequency support. Taking into account of the frequency regulation capacity demand for PVs and the operation benefits of PVs, a WAMS-based method to calculate the deload margin for PVs is proposed in this paper. In addition, the corresponding droop control strategy is designed to make full use of PVs´ reserve capacity. An isolated industrial system for aluminum production driven by coal-fired power and large scale PVs is studied as an example case. Simulation is done with real-time digital simulator (RTDS) platform and results verify the effectiveness of the proposed frequency regulation strategy.