An overview of hybrid systems consisting of synchronous condensers and battery energy storage system to support power grid

As wind farms are integrated into power systems, synchronous condensers (SCs) could play an important role in support of reactive power, inertia, short-circuit current, and working as a voltage source. In practical projects and various places, the deployment of SC has verified its functions, and the stability of the power system has been improved. Battery energy storage system (BESS), as a relatively mature energy storage technology, can bring frequency support to the power system. Therefore, it also retains the advantages of power electronics, providing reactive power and a fast response to the power system. In this paper, we review the development of both techniques and discuss the future feasibility of hybrid systems. In addition to analyzing the existing hybrid systems of SC and BESS in parallel, we also propose a novel type of hybrid system, which may be one of the development directions of hybrid systems and renewable energy power systems.