고장 상황에서 계통 재구성 및 MMC 제어를 고려한 신뢰도 기반 AC/DC 하이브리드 배전망 계획 방안

Abstract

Amid the global energy transition toward carbon neutrality, renewable energy deployment is rapidly expanding worldwide. However, the rapid expansion of renewable energy is revealing the technical limitations of existing alternating current (AC) systems, causing issues such as reduced power grid flexibility, system stability problems due to intermittency and high variability, and connection waiting issues in distribution networks. As a promising alternative, MVDC (Medium Voltage Direct Current) based AC/DC hybrid distribution networks can increase renewable energy integration capacity by up to 60% and improve line load capacity by more than 30%. While operational aspects of AC/DC hybrid systems have been extensively studied, research on initial system design and construction remains insufficient. This paper proposes a planning approach that considers not only economics but also operational optimization during fault conditions in the initial AC/DC hybrid distribution network planning stage. For distribution reliability index calculation, the approach integrates existing system reconfiguration methods with MMC dynamic voltage and power control schemes, while addressing uncertainties of renewable energy output variations and load fluctuations through a two-stage robust planning framework.