A study on influence of ramp-up of aggregated power output of photovoltaic power generation on electric power system frequency

This paper examines the influence of ramp-event of aggregated power output fluctuation of photovoltaic power generation system (PVS) on the power system frequency. A numerical simulation model of economic load dispatching control (EDC) and load - frequency control (LFC) is utilized together with a PVS power output forecasting model and a unit commitment (UC) scheduling model developed in our preceding study. In the case of ramp event with long duration and rapid ramp rate, the power output of controllable generators with high load following capability reaches to the limit even though the power output change of low load following capability generators is still available. As a result, the frequency deviation from the acceptable range occurs. When the load dispatch scheme is temporary switched from the conventional EDC using an equal incremental fuel cost rule to the dispatching based on the capacity without the consideration of fuel cost, the aggregated load-following capability can be preserved and the frequency deviation can be avoided.