A novel approach is presented for efficientlymodeling a power system which indudes pardel-connectedHVAC, and HVDC transmission systems. The proposed modelhas been dehved for a system in which an AC generator isconnected to an infinite bus system through a parallel AC lieline and a ITVDC link In addition to state-spacerepresentation, a block diagram representation has beenformed to analyze system stability. In this new block diagramrepresentation, the dynamic chsractenstks of the system areexpressed in terms of a newly developed H constant. Thedevelopment of the block diagram and associated H constantsare explained. The new model is evaluated usingPSCAD/RTDS real time digital simulation. Based on this newmodel, the low frequency oscillation phenomenon in pardelAC/DC system is studied and the results are show
