INCREASING WSCC POWER-SYSTEM PERFORMANCE WITH MODULATION CONTROLS ON THE INTERMOUNTAIN POWER PROJECT HVDC SYSTEM

The interconnected power system in the western U. S. and Canada, designated as the Western Systems Coordinating Council (WSCC), has two dc lines that transmit power for long distances across the system. One of these dc lines, the Intermountain Power Project (IPP) dc transmission system, parallels the east to west ac system transmission. The existing ac system has some limitations on power transfers due to power system oscillations at the higher power transfer levels. Utilizing the fast power control available in dc systems, modulation controls on the IPP dc transmission system for improving the performance of the interconnected power system were investigated. This paper describes the improvements in power transmission capacity that can be achieved by adding modulation to this dc system.