Prediction of voltage collapse in an integrated AC-DC network using the singular-value decomposition concept

Abstract

Abstract A power system under heavy loading conditions may face the problem of voltage instability followed by voltage collapse. The minimum singular value of the AC power flow Jacobian has been popularly used as a static voltage stability index showing the distance between the steady-state operating point and the point of voltage collapse. In this paper, the concept of minimum singular value and condition number of the load flow Jacobian has been extended to study the voltage instability of a combined AC-DC system. The proposed method has been applied to determine the voltage collapse point in four sample AC-DC systems, three of them derived from the IEEE 14-bus system and the fourth a practical 156-bus Indian system. The model includes a switching scheme to check the converter control parameter limit violations. The effect of load changes at a single bus as well as at all the buses simultaneously on voltage collapse has also been studied.