A Novel Operation Strategy of Battery-Supercapacitor Hybrid Energy Storage System Providing Frequency Regulation Service

Regulation services (RSs) play a crucial role in sustaining the stability of electric power grids by minimizing the instantaneous mismatches between electric power generation and load demand. RS providers dynamically inject/absorb the electric power to/from the grid, in response to regulation signals provided by independent system operators (ISOs), in order to guarantee the stable operation of electric power system. The regulation signals are highly transient and require quick response from the RS providers. In this paper, a state-of-the-art hybrid energy storage system (HESS) based upon battery energy storage (BES) and supercapacitor (SC) technology is employed to provide frequency regulation in electric market. An innovative algorithm is proposed to operate the HESS effectively. The proposed algorithm does not lose any small piece of information supplied by ISO through the regulation signal which is a drawback in filter based techniques. The algorithm is fast, simple and easily implementable. As a case study, a real world frequency measurement signal covering a calender year with 6 sec resolution is used to test the proposed methodology. Simulation results depict the effectiveness of the proposed approach.