Voltage Stability Assessment and Improvement Index using Load Shedding and a Shunt Capacitor

Abstract

Voltage stability of large interconnected power systems has been recognized as a complex problem for identifying the fundamental mechanism of voltage stability due to the multiplicity of power system operation and control components, complicated configuration, and overall performance of the systems. Heavy loading and system faults are factors that contribute to voltage instability in power systems. Treating heavy loading at stressed buses necessitates the selection of the appropriate bus, which has become difficult to find and predict, especially in an interconnected system. In this paper, a voltage stability assessment index is derived using linear algebra and the Singular Value Decomposition (SVD) and Pseudo-inverse of the power flow Jacobian matrix. Singular values and the right eigenvector are used as load shedding recognition indicators. Meanwhile, VSM (Voltage Stability Margin) improvement is being pursued through load shedding with sensitivity ranking for the assessment index, and installing a shunt capacitor at the most sensitive bus bar for obtaining a better P-V Curve. Finally, the study was tested on IEEE 14-bus as a case study.