Abstract
This paper proposes a novel method to identify the area where the power flow can be controlled by phase shifters. In the proposed method, first, the minimum number of phase shifters necessary for the control of power flow in an entire network is determined as the number of co-trees. Since the set of co-trees is not unique, there exists several allocations of phase shifters. Next, the features of controllable area with respect to each allocation are extracted as the eigenvalues and eigenvectors of the matrix, which represents sensitivities of power flows to control angles of phase shifters. The extracted features are applicable to the determination of phase shifter allocation from the viewpoint of flexible power flow control in network open access environments. The effectiveness of the proposed method is confirmed through the simulation studies of two model systems.