APPLICATION OF STATIC VAR COMPENSATORS TO INCREASE POWER-SYSTEM DAMPING

A theory to analyze power system damping enhancement by application of static var compensators (SVC) has been developed based on the well-known equal area criterion. Some fundamental issues as the SVC effect on a power system, how to control an SVC to improve system damping, the differences between continuous and discontinuous control of SVC reactive power output and the best SVC location in a power system to achieve the maximum damping improvement are discussed. Based on these discussions a discontinuous SVC control approach is proposed, in which the change of SVC reactive power output at discrete points is determined by the power deviation on a transmission line. The time-domain simulations of the proposed control approach in a one-machine system to increase swing oscillation damping and in a 4-machine system to increase the damping of an interarea oscillation mode demonstrate that the developed analysis theory and the proposed SVC control approach may be applied to solve practical power system damping problems.