Small signal stability program analysis of SVC and HVDC in AC power systems

High-voltage DC transmission links and static VAr (voltampere reactive) compensators (SVCs) have controllable characteristics with potential for affecting system stability. To study these effects and to design their controllers for improving system stability, there is a need for their representation in small-signal stability programs as well as time simulation programs. The formulation of DC link and SVC models and their controllers for small-signal stability are addressed. Several examples are studied to show the capability and application of the small-signal DC link and SVC models. The small-signal results are verified by time-domain simulation results of the same study cases. Modes obtained by spectral analysis of the time simulation results are very close to those obtained by small-signal stability analysis. >