A new hybrid method for on-line dynamic security assessment

This paper presents a new hybrid method called marginally unstable injection (MUI). This method incorporates energy function analysis into a time-domain simulator for transient stability assessment. Using a 'controlled' sequence of short pseudo-faults and the concept of slow energy function (SEF), the proposed method provides an improved stability index by impelling a stable system to a marginally unstable state. The resulting stability index is then utilized for estimating the amount of generation rejection required to maintain transient stability within the framework of on-line dynamic security assessment. The technique developed is applied to a 700-bus North America system. (C) 1998 Elsevier Science Ltd. AII rights reserved.