Generator Reactive Power Constrained Voltage Stability Analysis of Large Power System Under Critical Line Outage

Heavy loads and large disturbances are usually manifested into voltage instability of power systems. The increased transaction levels in open access power systems are main cause of stressful operation of the system. Several countries around the globe have reported incidences of voltage instability in recent years. It has become a top priority of power engineers to solve voltage instability related problems and control the voltage profile. Action of Automatic Voltage Regulators (AVRs) of the generators is the first line of defense against voltage instability. The challenge of maintaining power system voltage stability and security under outage conditions is well taken by the power system engineers. The security assessment in the event of a contingency provides the knowledge about the current and future system state. When generator reactive power is automatically regulated, the voltage stability is improved. In present studies IEEE 6 Bus Power system is considered for static voltage stability. The co-relationship of upper limits of generator reactive power with voltage stability and maximum system loadability under critical line outage is established.