Analytical investigation of the use of static VAR compensators to aid damping of inter-area oscillations

A comprehensive investigation of the use of Static VAR Compensators (SVCs) to aid damping of low-frequency inter-area oscillations in large interconnected power systems is presented. The study of inter-area oscillations and the design of controls is done using modal analysis of a linearized model of the power system. Based on this model an efficient algorithm to compute the power oscillation flow for each mode of concern is developed. This approach allows to identify the nature of oscillation patterns and provides important information needed in the application of SVCs. Controllability and observability measures are then used to assess the impact of dynamic voltage support on system damping as well as to identify optimal locations for SVCs. The influence of system structure and load effect on the SVC performance is discussed. Detailed time-domain analyses are finally performed to check the validity of the analysis and to assess the impact of dynamic voltage support on system transient behaviour.