A short-circuit calculation solver for power systems with power electronics converters

Abstract

Power electronics converters have been widely deployed in modern power systems in different voltage levels. The complex operation characteristics of power converters, which combine different control modes and various current saturation states, are also significantly changing the power systems’ behavior in fault conditions. The objective of this paper is to develop a steady-state short-circuit calculation solver for power systems with power electronics without the need of detailed dynamic models. In particular, the steady-state operation equations related to the converter control are included in the system formulation. An extended Newton–Raphson (NR) solver is proposed to compute the short-circuit equilibrium point that considers converters’ operation limits. Also, an iterative algorithm is presented in order to efficiently identify the current saturation states of power converters under a specific short-circuit fault scenario. Case studies have been presented with several power systems with voltage source converters (VSCs). Dynamic simulations are included to validate the accuracy of the proposed methodology.