A refined method for optimising inverter loading ratio in utility-scale photovoltaic power plant

This paper proposes a novel approach for designing the inverter loading ratio (ILR) for utility-scale PV systems. As the first of its kind, a deterministic approach is proposed for dealing with such a design issue. The design objective is to maximise the economic reliability of the photovoltaic (PV) Plants. The problem is reformulated using a linear programming (LP) technique. The proposed solution allows dealing with each system individually and requires only the information of the DC/AC power conversion unit system. The results are tailored for utility-scale PV systems but can also be easily revamped for residential and private/industrial installations. The results were validated using a real-world case study of a utility-scale PV power plant in Ireland, operating under the Renewable Electricity Support Scheme (REFIT) feed-in tariff. These results were compared with the design method from the commercial PVsys software. In the proposed case study, reducing the ILR value from 1.4656 (as designed by PVsys) to 1.4528 led to an increase in annual profit annuities, demonstrating the effectiveness of the proposed approach.