WSCC voltage stability criteria, undervoltage load shedding strategy, and reactive power reserve monitoring methodology

Engineers have long been struggling with developing voltage stability criteria for their systems. The development of the criteria becomes even more difficult if one attempts to apply the criteria to an entire region such as the one within Western Systems Coordinating Council (WSCC). The WSCC which is comprised of 86 member systems from the western region of North America (Canada, Mexico, and US) has developed strict voltage stability standards which must be complied with by all member systems. The purpose of this paper is to describe the WSCC system-wide voltage stability criteria, which are based on V-Q and P-V methodologies. A methodology for determining the proper mixture of static and dynamic reactive power source, an undervoltage load shedding strategy, and a reactive power reserve monitoring methodology are also discussed