A Comparative Study of Electromagnetic Transient Simulations using Companion Circuits, and Descriptor State-space Equations

Abstract

This paper investigates an alternative method for EMT simulation of power networks, which uses Descriptor State-space Equations (DSE) to represent the dynamical equations of the circuit. An automated procedure to formulate the DSEs directly from the circuit's netlist is presented. Once formulated, the DSEs can be discretized using the trapezoidal integration method, and subsequently used for EMT simulations. This approach is compared with the widely used Companion Circuit (CC) approach. Advantages and disadvantages of each approach are discussed. Finally, a procedure for interfacing a DSE-based formulation with a CC-based EMT simulator is also presented. This procedure enables interfacing of arbitrary power networks with a commercial CC-based EMT simulation package and can also be used to speed up the simulation using parallel processing.