Voltage stability assessment index for recognition of proper bus for load shedding

Abstract

Nowadays, voltage stability of large interconnected power systems due to the multiplicity of the power system operation and control components, complicated configuration and overall performance of the systems have been recognized as a complex problem for identification of the fundamental mechanism of voltage stability. Contributory factors to voltage instability in power systems are heavy loading and faults occur in the system. Treating to alleviate heavy loading at the stressed bus requires selection of the proper bus, and it became a challenge to find and predict it easily especially in an interconnected system. In this paper, an assessment index of voltage stability is derived with supports of linear algebra through the Singular Value Decomposition (SVD) and Pseudo-inverse of the power flow Jacobian matrix. Singular values and right eigenvector are applied as indicators of load shedding recognition. Meanwhile, VSM (Voltage Stability Margin) enhancement is pursued through load shedding with ranking of sensitivity for assessment index. Finally, the study is tested on the IEEE 14-bus and 23-bus case studies as a point of reference were carried out to illustrate the effectiveness and accuracy of the proposed assessment index.