Voltage collapse scenario search

A cascading failure involves seemingly unexpected loss of many critical components such as transmission lines and generators. A cascading failure often leads to separation of the system into islands and results in the loss of a substantial amount of load. It is highly desirable, but extremely difficult, to design and operate a power system such that the ill effects of a cascading failure can be minimized. Cascading failures have been extensively studied after their occurrences. No systematic method exists for analyzing the risk of cascading failures for a given system operating condition, simply because there are too many scenarios to study for exhaustive search of cascading failures. This paper describes new procedures developed for nonexhaustive search and evaluation of multi-contingency scenarios leading to voltage collapse. The tie-cutting algorithm selects line outage scenarios and the Q-reduction algorithm selects generator outage scenarios. Voltage collapse scenarios were evaluated in terms of PV curves through the generator approach and LFC simulation. The August 10, 1996 WSCC disturbance is selected as an example scenario for reference, and the effectiveness of the newly developed procedures is demonstrated on the WSCC study system model.