DEVELOPMENT OF A CONTROL-SYSTEM FOR A HIGH-PERFORMANCE SELF-COMMUTATED AC DC CONVERTER/

A self-commutated ac/dc converter composed of controlled turn-off devi ces to be applied to future system interconnection is described. The a dvantages of a control system for this type of converter are: (1) Comm utation does not fail when the system voltage is decreased or distorte d by a power system fault. (2) It needs no equipment for reactive powe r supply, such as static capacitors or synchronous rotating condensers , when used in a low short-circuit capacity power system. (3) It can i ndependently control active power through de lines and reactive power from each terminal. The proposed back-to-back (BTB) control system usi ng the voltage margin method was verified with a power system simulato r, and the results demonstrated the excellent features of the high-per formance self-commutated converter.