Damping for the Northwest - Southwest Tieline Oscillations - An Analog Study

Oscillations which developed on the initial transmission tie between the Northwest and Southwest systems brought about trip-outs and threatened to limit its usefulness. The analog study described reveals much about the nature of the oscillations and shows some unusual relief measures to be possible. While sources of the negative damping were indicated to be such that correcting them directly might be impracticable, means of offsetting them with stabilizing effort developed by special control of fast responding generation are proposed. The required stabilizing effort is indicated to be within the capability of a large nonreheat steam unit. This amount is startlingly small for influencing such large systems.