Investigation Study on the Voltage Stability Status of a Power Flow Problem Solution

This paper presents an investigation study to verify the voltage stability status for a power flow problem solution. After solving the power flow problem (PFP) by the Newton-Raphson (NR) method, the voltage stability problem is evaluated. The voltage stability analysis employs classical techniques based on Q-V curves, V-Q sensitivities and modal analysis. The main purpose is to evaluate the voltage stability associated to the system operation point and identify possible instability related sites which causes this problem. In order to illustrate the importance of the study, experiments are carried out by using a 6-, 118-, 300-, 2746- and 9241-bus system. Some of these systems show clear instability voltage problems, which are associated to unstable figures. Results in terms of Q-V curves, V-Q sensitivities, computation of eigenvalues and participation factors are important figures obtained to evaluate the voltage stability status of the system operation point. This aspect can be useful since it provides a tool to determine an adequate reactive support for a specific studied system.