Development of Cross-border Load Frequency Control for the Japanese Power System

This paper presents a cross-border load frequency control (LFC) scheme planned for implementation in the Japanese power system in 2026. LFC is a critical function that regulates system frequency and tie-line power flows by adjusting secondary control reserve (SCR) outputs to minimise the area control error (ACE) in each control area. Traditionally, Japanese transmission system operators (TSOs) have procured SCRs within their own control areas, using LFC to reduce ACE. However, increasing integration of renewable energy has increased frequency disturbances and reduced SCR availability. Rising energy prices also call for more economical SCR operation. To address these challenges, cross-border activation of SCRs – enabling coordination between TSO control areas – has been proposed. This study…