Design of robust voltage control system for improving transient and voltage stability on distributed generation expansion

This paper presents a design of robust voltage control system for improving transient and voltage stability in the power system where distributed generations (DGs) are gradually increased. If DGs are installed more and more, the problems related to transient phenomenon or voltage variation due to output variation of DGs may become severe and can make the system unstable. In this paper, a solution to mitigate those problems is proposed by renovating voltage management system (VMS) already installed in Jeju Island, South Korea. The solution consists of two additional controllers, which are transient mitigation controller (TMC) and voltage regulation controller (VRC). The TMC induces supplementary signal to reactive power dispatcher (RPD), which is a component of the VMS, to mitigate transient phenomenon shortly after disturbances such as load or DG trip. The VRC is designed to reduce voltage variation caused by output variation of the DGs. The performances of the proposed robust voltage control system are carried out by time domain simulation in the Jeju island power system with real-time digital simulator (RTDS) which is a fully digital power system simulator in real-time.