Resilience assessment of coordinated energy storage assets in low-carbon grids

The resilience of power systems to extreme events is under increasing threat due to the high penetration of renewable generation. This paper examines the strategic use of energy storage to ensure the resilience of a low-carbon grid with different penetrations of renewable generation. Through real-time simulations of the loss of transmission lines or generators, coordinated energy storage assets are used to reduce frequency deviations and maintain load supplies. Based on simulations of the modified IEEE nine-bus system in RTDS, the influence of storage location and capacity are analysed. Results indicate that increasing renewable power penetration from 30% to 70% causes the lowest frequency after a disturbance to drop from 48.17 Hz to 47.48 Hz (based on a 50-Hz grid) when the two most sensitive transmission lines are lost, and the load shedding ratio increases from 0.50 to 0.60. Installing storage at a load-connected bus is seen to be most effective in this example network to improve resilience. For example, increasing storage capacity to 42.5% of system capacity reduces the load shedding ratio from 0.5 to 0.0 when two lines are lost with up to 60% renewable penetration.