A distributed and coordinated voltage control scheme considering voltage recovery

This paper presents a coordinated emergency voltage control scheme against long-term voltage instability. It uses a set of distributed controller groups, each controller monitors load voltage in a zone and takes local actions to keep the system voltage stable. Emergency actions are coordinated and optimized with information exchanges between controllers, an action criterion is introduced to avoid excessive load shedding by judging the evolution of local voltage recovery condition, which minimizes the total control cost on the basis of fast voltage restoration. The operation, design and effectiveness features have been demonstrated by the case studies on a 12-bus sample network.