Digital simulation of an AC/DC system in direct-phase quantities

This paper describes a mathematical model for the simulation of an AC/DC system using direct-phase quantities. This system consists of an AC/DC converter station connected to a synchronous generator at its terminals as well as to an infinite bus-bar through a short transmission line. The proposed model in direct-phase quantities enables the study of the effects of the generated harmonics of the DC transmission on AC systems in general and on the behavior of synchronous machines in particular. The paper describes also a numerical solution using a digital computer for the mathematical model of this AC/DC system. The usefulness and versatility of the computer program are demonstrated by applying it to different AC/DC system configurations. The paper gives results of some studies concerning the effects of the generated harmonics on the behavior of synchronous machines with or without filters in the system.