Loop power flow control to minimize power losses and augment voltage stability

This paper presents a method to optimize power flows in a power system with a loop structure by controlling the line reactance, which realizes the augmentation of voltage stability as well as the minimization of power transmission losses. A series variable reactance is capable of controlling the power flow directly, when it is installed in a looped power system. First, the object function for loss minimization is formulated as a quadratic function of a closed-path power flow, by which the optimal solution is systematically derived. The optimal state is achieved by several combinations of series capacitors installed in some of lines among the closed-path. Thus, series capacitors can be properly assigned so as to augment the voltage stability by enhancing the bus voltage with the critical P-V characteristics. The proposed method should be an effective tool for the power traffic control in a deregulated power system with multilateral power transactions since the optimal solution is systematically obtained for a given power flow condition