Assessment of Voltage Stability Indices for Determination of Power System Weak Buses

Abstract

The ever growing population and the high level of industrialization globally has led to increase demand for electric power. However, the expansion of electric power generation as well as transmission and distribution power system has been limited by financial constraints. This has led to operation of power system close to its operating stability limits. This overloaded operation condition of power system leads to instability challenges like voltage instability due to inability of the power system to supply required reactive power. In the case that voltage stability status of a stressful system not determined and the challenges arising not addressed, this can lead to voltage collapse and total blackout of the system. Hence there is need to constantly check the status of voltage stability and determine voltage collapse proximity and plan counter corrective measures accordingly. This paper aims to compare Fast Voltage Stability Index (FVSI) and Line stability Index (Lmn). These line voltage stability indices indicates the proximity of power system lines to voltage instability. This will help power system planners and operators in their daily power system operations. The standard IEEE 30 bus power system was used to carry out this research and test performance of these voltage stability indices.