Comparison of Stability Indices for Critical Line at Different Loading Conditions

Abstract

Modern power systems are operating under much stressed load conditions and also facing the problem of limited capacity of power generating sources. Voltage instability is a quite frequent phenomenon under such situation rendering degradation of power system performance. In order to avoid system voltage collapse and blackouts, power system is to be analyzed in view of voltage stability for a wide range of system conditions. This paper discusses the use of line voltage stability indices termed as fast voltage stability index (FVSI) and line stability index (Lmn) in order to determine the critical line. The line with least stability margin is ranked highest indices value is identified as theoretical line. The performances of the indices are investigated for the IEEE 14 - bus test system at different loading using MATLAB simulations.