抄録
DC transmission systems are widely considered as recent control techniques to opetate convetional electric power systems and stabilize thier dynamic behavior. Then, it is important to clarify stability regions in the power systems with dc transmissions in terms of transient stability. The authors have numerically reported the stability region in an ac/dc power system based on a differential-algebraic equation. In this paper, the global structure of stability region is discussed analytically and numerically.