Refinement of Generation Schedule and Under-Frequency Load Shedding Protection Scheme for Nangan-Beigan Islanded Power Grid in Taiwan

The Nangan-Beigan power grid in Taiwan has faced frequent blackouts in recent years, primarily due to operating at approximately half of its generation capacity, which led to vulnerability during consecutive N-l-l and extreme N-2 generator tripping events. To address this issue, this power grid occasionally shifted to a mode where a single generator operated at over 70% of its capacity. However, this approach increased the risk of a complete blackout. To mitigate this risk, this paper describes the refinement design of the existing load shedding protection scheme for the Nangan-Beigan power grid. The refined scheme includes an updated generation schedule and an enhanced under-frequency load shedding (UFLS) strategy. This refinement accommodates both the half-capacity operational mode and the higher-capacity mode of single-unit operation. The improved load shedding scheme is more effective since it requires less load shedding as blackout conditions approach compared to the previous scheme. The effectiveness of these refinements has been demonstrated through comprehensive computer simulations and practical operational data. It is our belief that the insights gained from this refinement will help power engineers in designing more effective load shedding protection schemes for power grids.