Advanced Modeling & Fast Simulation Algorithms for Cascaded Two-Level Converters

Abstract

Cascaded two level converters (CTL) are gaining prominence with increased installations world-wide in high-voltage direct current (HVdc) systems. The simulation of CTLs is important to assist with the design of hardware, control systems, and planning of power system expansions. However, the simulation of CTL-HVdc using existing software takes a long time due to the presence of a large number of states and non-linear devices. An ultra-fast single- or multi-CPU simulation algorithm to simulate the CTL-HVdc system based on state-space models, hybrid discretization algorithm with a relaxation technique that reduces the imposed computational burden, and a multi-rate method is presented in this paper. The developed algorithm is validated with respect to reference PSCAD/EMTDC model.