Basic Study on Method of Load Frequency Control in Consideration of BESS Output in Governor-free Control

A load frequency control (LFC) becomes more difficult by the strong growth of renewable power generation. One of the promising measures to support LFC is a battery energy storage system (BESS). Frequency deviation (Δf) can be more effectively suppressed by using BESS for governor-free (GF) control (Case-G) than for Merit-Order based LFC (Case-L). However, kWh capacity of thermal power plants required for LFC in Case-G is larger than those in Case-L because the output of BESS is not taken into account in LFC. Therefore, this study proposes a LFC in consideration of BESS utilization for GF (Case-GFB). As a result, kWh capacity of thermal power plants required for LFC is reduced in Case-G-FB compared to those in Case-G. In addition, the peak of Δf in Case-GFB is a little smaller than those in Case-G because of adjusting the feedback value in consideration of Δf changing property.