ABSTRACT
In the reliability studies of power systems, adequacy and operating reliability are the two terms used. The first term, adequacy, is defined as the ability of the electricity system to supply the aggregate electric power demand and energy requirements of the end-user customers at any instants. It is needed to take into consideration the scheduled and reasonably expected unscheduled outages of system elements. The other term needs to be taking, as well; in consideration is the operating reliability, which is the ability of the bulk-power system to withstand sudden disturbances. Some of the disturbances are the electric short circuits or the unanticipated loss of system elements from credible contingencies while avoiding damage to equipment or uncontrolled cascading blackouts.
