The Strategy Control of Islanded Microgrid Using Battery´s State-of-Charge

The micro grid is operated in the grid-connected mode and the islanded mode according to the upstream grid. Commonly, micro grid operates the grid-connected mode. But, when a fault occurs in the upstream grid, it should disconnect and shift into islanded operation mode. It is important to maintain the voltage and frequency constant values in islanded mode. To achieve these management goals appropriately, In this paper, a strategy control of state-of-charge (SOC) for the energy storage system operating under micro grid islanded mode to stabilize the frequency and voltage was proposed. The SOC control is to keep the charging level of the battery within its proper range while the battery was output or absorb the power. And then control of gird voltage and frequency. The performance of suggested SOC control was simulated by PSCAD/EMTDC. As a result, output characteristic of BESS applied SOC control is more realistic than not applied SOC control.