A STRUCTURE-PRESERVING ENERGY FUNCTION FOR STABILITY ANALYSIS OF AC/DC SYSTEMS

Direct stability analysis of AC/DC power systems using a structure-preserving energy function (SPEF) is proposed in this paper. The system model considered retains the load buses thereby enabling the representation of nonlinear voltage dependent loads. The HVDC system is represented with the same degree of detail as is normally done in transient stability simulation. The converter controllers can be represented by simplified or detailed models. Two or multi-terminal DC systems can be considered. The stability analysis is illustrated with a 3-machine system example and encouraging results have been obtained.