On-line voltage stability assessment strategy considering limit of voltage source

Based on a equivalent model of power network, voltage stability index is obtained from power transfer limitation in this paper. More, considering the regulation capability of voltage source, an on-line voltage instability assessment scheme is proposed. The index is defined to monitor remaining voltage regulation capability of voltage source point. As some voltage source has no enough regulation capability, the impact of loss this voltage supported point on voltage stability is evaluated. Simulation results based on the typical power systems demonstrate that the proposed method can identify the dangerous condition and capture the critical coming voltage source limitation, which adapts to on-line voltage stability assessment.