Grid-connected advanced energy storage scheme for frequency regulation

Abstract

Secure and economic operation of the modern power system is facing major challenges these days. Grid-connected Energy Storage System (ESS) can provide various ancillary services to electrical networks for its smooth functioning and helps in the evolution of the smart grid. The main limitation of the wide implementation of ESS in the power system is the high cost, low life, low energy density, etc. However, improved battery technology is changing the scenario rapidly. Also, any mismatch in power demand and supply causes fluctuation in frequency. Therefore, this paper presents a way for reducing the frequency fluctuation using an Advanced Energy Storage System with utility inductors. To compensate for the mismatch of supply and demand, a new system is proposed so that the nominal frequency of the power system is maintained. Due to the very high penetration of energy systems, there is a need for frequency regulation, hence different control strategies are employed to overcome this problem. In case of extreme power supply, the ESS acts as a load and gets itself charged whereas during the power deficit the ESS supplies power to maintain balance in demand and supply, and hence it mitigates the frequency fluctuation. The simulation model contains an ESS connected to a grid with a varying commercial or residential load profile. Simulation results illustrate the effectiveness of grid-connected ESS in minimizing frequency variation.