DETERMINATION OF COMMUTATING VOLTAGE AND COMMUTATION REACTANCE AND COMPUTATION OF 3-PHASE AC DC POWER FLOW

This paper presents a rigorous method of determining the commutating voltage and the commutation reactance, both of which play significant roles in the analysis of AC/DC power systems under unbalanced AC conditions. An accurate but simple three-phase no-mutual equivalent circuit is derived for the AC part connected to the three-phase converter bridge. By using the circuit, the analyses relevant to AC/DC power systems under both steady state and dynamic unbalanced conditions could be performed more precisely and more concisely. As an application, three-phase AC/DC power flow is also discussed. A set of complete but minimized converter equations is developed, with which the computational requirements of the power flow could be reduced.