Study of a major oscillations event in northeastern area of the Iranian power network

Iranian power system encountered major oscillations in January 2008 in the northeastern area with an amplitude of about 120 MW. Since not all the events and variables had been recorded, a scenario to simulate the recorded oscillations and results of studies conducted to reproduce the oscillations by simulation are discussed in the first part. Tuning of supplementary controllers, such as PSSs, on the generating units and the use of reactive power compensators in the long transmission line to enhance stability and eliminate severe oscillations between the north and eastern areas are investigated in the second part. Eigen-value analysis and participation factors are used to appreciate the nature of oscillations and the required PSS settings. The results show that, by using the properly tuned PSSs and accurate compensation of the reactive power, transient stability and damping of oscillations are considerably improved.