The research presents a study in evaluating the performance of several voltage stability index has been proposed and it is named as the power transfer stability index. The proposed index is then compared with other known voltage stability indices such as the voltage collapse prediction index, the line index and power margin. To evaluate and compare the effectiveness of these indices in predicting proximity to voltage collapse, simulation are carried out using the WSCC 9 bus test system. Simulation test result show that the proposed power transfer ability index and the voltage collapse prediction index give a better prediction of dynamic voltage collapse comapared to the power margin and the line index.