Modal Analysis for Voltage-Stable Regime Determination: The Nepalese Power System Case

Abstract

Voltage stability is a vast subject, which covers a substantial area in power system analysis, such as uniform voltage profile, reactive power balance, and feasible operation of the power system. The study and understanding of voltage stability are not only crucial but also very helpful in the safe operation of a power system. This paper presents an implementation of modal analysis in voltage stability. Here, we propose to use of voltage-reactive power relations from the load flow jacobian matrix to establish a V-Q sensitivity relationship and study the unstable modes in a real-time power system of Nepal. This paper also describe a heuristic approach to bring back an unstable system to a stable operating regime using the results of modal analysis, and further analyze the root cause behind the instability inherent in the first place.