Reformulated model based modeling and simulation of ungrounded stiffly connected power systems

Features of ungrounded stiffly connected power systems have driven the development of strategies for detailed modeling and simulation for transient stability analysis. In this paper, a new generalized strategy is proposed for modeling and simulating ungrounded stiffly connected power systems. The proposed strategy neglects the minimal effects of line capacitances on system dynamics to achieve significant improvement in simulation speed. Since interconnection incompatibility occurs when neglecting capacitances, one component model is reformulated on each resistor or inductor bus to derive the voltage inputs of the interconnected component models. Systematic procedures are developed to build the model of an ungrounded stiffly connected system with a set of Differential-Algebraic-Equations (DAE) in the environment of Matlab/Simulink. The authors contrast their approach with two conventional power system simulation programs and a method reported in literature. By modeling and simulation of an example ungrounded stiffly connected power system, the feasibility of the proposed method is demonstrated.