Voltage Stability of Power System using PV Curve and PMU data

This paper describes a voltage stability indicator that can be used to determine the proximity to system collapse by power system operators. The proposed PV curve method to determine voltage instability is compared with the existing voltage collapse proximity index (VCPI). VCPI is indicative of critical transmission lines whereas the PV curve analysis is indicative of critical buses. Phasor Measurement Unit (PMU) data facilitates in quick calculation and presentation of the indices to the system operators. The drawbacks of VCPI and how PV curve method is better than VCPI are presented. The simulations have been carried out in Real Time Digital Simulator (RTDSTM) using the New England IEEE 39 bus system. The indices accurately quantify the closeness of the power system towards instability. A slope monitoring method has been used to take restorative actions for the system to return to secure operating conditions.