AC DC HARMONIC INTERACTIONS IN THE PRESENCE OF GIC FOR THE QUEBEC NEW-ENGLAND PHASE-II HVDC TRANSMISSION/

During the spring of 1991, several severe geomagnetic disturbances wer e recorded in North America, and particularly in Northern Quebec, wher e Hydro-Quebec's La Grande generation complex and transmission system are located. As a result of these disturbances, the Quebec-New England Phase II HVDC system was affected by transformer saturation and harmo nic voltage distortion due to geomagnetic induced current (GIC). This paper presents an analysis of the phenomenon observed at Radisson, the northernmost terminal in the system. A central issue which is discuss ed in the paper is the reflection of the dc side impedance to the ac s ide for operating converters, and the effect of this reflection on the harmonic impedance as viewed from the ac side.