Abstract
This paper proposes a design method of damping controllers of two facts devices, namely Synchronous Voltage Source when it is used only for reactive shunt compensation, i. e. ‘Advanced Static Var Compensator’ (ASVC) and Static Var compensator (SVC). The applications of ASVC and SVC for damping control are demonstrated and the comparison is made about the damping control capabilities paying attention to the difference in the design philosophy and detailed dynamic performances. An important issue in designing this kind of controllers is to suppress overvoltage that appears under large disturbance. This overvoltage problem sometimes appears in the existing SVC system. To cope with this overvoltage problem, it is proposed to use the control sensitivity function to regulate indirectly the controller output so that the overvoltage problem is treated in the design step. Another important issue is that we point out the zero problem tends to appear inherent in a typical ASVC system making the controller design difficult. To design robust controllers under this condition, we suggest to use the bilinear transform to design a robust H∞-optimal controller. It is shown that the proposed controller provides more robust stability and better performance for additional damping for power system oscillations while suppressing overvoltages. Performance comparison is also made between ASVC and SVC cases.
