Study of Voltage Stability Indices Suitable for Online Applications

Ch V V S Bhaskara Reddy

Modern power systems are operating close to their maximum loadability limit due to various economical, geographical, environmental and operational issues. Sometimes, these operating conditions lead to instability of power system. The instability in power systems is due to rotor angle issues or voltage related issues. In this article, two methods used to predict the voltage instability of power system are discussed. The methods discussed are Voltage Stability Risk Index (VSRI), and Improved Voltage Instability Monitoring Index (IVIMI). The VSRI and IVIMI are developed by using time series data and are suitable for online purposes. Study of these indices was carried out on Northern Region Power Grid 246-bus test system.