Using quality control center to improve power system stability

Several designs of flexible electric power delivery system have been proposed to meet the demand for unbundled power quality. One such conceptual design is the so-called quality control center (QCC), where distributed generators (DCs) are expected to play a central role. In this paper, a new system stability control strategy is proposed by taking the advantage offered by the QCC. A dynamic model is developed for a power system that consists of a UPS-type QCC connected to an external generating-transmission system. The DG installed in the QCC takes the form of a microturbine. In the event of system frequency fluctuation due to upstream load-generation imbalance, the main generator and the DG are to regulate their output powers simultaneously to meet the load requirements. The objective is to mitigate the frequency variation. The main generator and the DG are designed to share the load power change equitably through a coordination strategy of the QCC. Simulation results confirm the validity of the proposed control scheme.