Power System Islanding Based on Slow Coherency

A method is proposed to determine controlled islands by grouping both load and generator buses simultaneously, from the measured voltage angles through phasor measurement units (PMUs), with Zolotarev polynomial based filter bank (ZPBFB) and singular value decomposition (SVD). ZPBFB decomposes the PMU signal into monocomponents for modal parameters. In the first step, ZPBFB is applied on the measured voltage angles to determine inter-area modes of each signal. SVD is applied on the monocomponents of the signals involved in an inter-area mode for determining coherent bus clusters. An algorithm is also developed in order to optimally allocate weak coherent buses to different controlled islands such that the power imbalance is minimum in each of the islands. The proposed approach is validated on IEEE four machine, two area test system.