Evaluation of Power System Stability using Voltage Proximity Index

This paper discusses the concept of performance indices used for evaluating the power system stability. These indices are helpful in determining an early vulnerable condition of the bus due to various perturbations such as sudden increase in load, line tripping. Among various indices, it was found that Voltage Collapse Proximity Index (VCPI) is one of the simplest and fastest indices to predict the propinquity of the collapse. This index can be used for both offline studies as well as for online implementation. It requires only modest amount of calculations with few parameters of the power system such as voltage and admittance values and hence it requires less time for its computation. In this paper an IEEE 14-bus system is considered and VCPI is calculated. From the results obtained it is seen that Voltage Collapse Proximity Index is an efficient tool in determining the steady state and dynamic state stability of the buses and thus ensuring the security of the system.