Enhancing Voltage Stability Assessment through Phasor Measurement-Based Voltage Estimation

Suresh Babu Palepu; M. Damodar Reddy

doi:10.37591/.v13i3.7643

Abstract

Voltage stability monitoring of real-time systems may benefit greatly from recent advances in Phasor Measurement Units (PMUs) technology. Based on measurements taken from PMUs at three different operating locations, this article suggests quadratic fitting of nose curves (loading factor against bus voltage magnitude curves). Comparisons between the proposed estimation of nose curves and an existing method of quadratic nose curve fitting based on two step continuation power flow have been made. The IEEE 14-bus system has been the subject of case studies. The suggested method uses the Power System Analysis Toolbox (PSAT) software to do a quadratic fitting of nose curves utilizing a two-step continuation power flow. According to simulation results on the IEEE 14-bus system, the nose curves derived by complete continuation power flow and those fitted quadratically using the two-step continuation power flow are very similar. However, the suggested method of constructing a quadratic nose curve using PMU readings yields very different voltage stability margins. This demonstrates that continuous power flow, which takes into account a static model of the power system, may not be useful in evaluating the voltage stability of dynamic systems when bus voltages are influenced by the dynamics of power system components. The suggested method of fitting quadratic nose curves using PMU measurements appears to be more efficient in determining the voltage stability of dynamic systems.