A Control Strategy for Battery Energy Storage Systems Participating in Primary Frequency Control Considering the Disturbance Type

In power systems, various types of disturbances can randomly affect the active power balance, which can result in unexpected frequency changes. A battery energy storage system (BESS) is an effective technique to assist power system primary frequency control. In this work, a comprehensive self-adaptive strategy considering load disturbance types is proposed that enables BESS participation in the primary frequency control of power grids. First, the different types of load disturbances in the power system are divided into two categories, namely, step disturbance and continuous small disturbance. Then, the advantages of virtual inertia control and virtual droop control are taken into full consideration. Model A and Model B are proposed to match the two load disturbance types. Model A is used to rapidly prevent sudden changes in frequency under step disturbance conditions without restricting the state of charge (SOC) of the BESS. Under the conditions of continuous small disturbances, we further propose Model B in which primary frequency control is realized while considering SOC recovery. Compared with the previous primary frequency control methods, the presented approach significantly improves the stability of complicated and changeable power systems. Meanwhile, it fulfills the frequency control requirements with superior frequency control performance.