INTEGRATED TREATMENT OF ADEQUACY AND SECURITY IN BULK POWER-SYSTEM RELIABILITY-EVALUATIONS

Traditionally, bulk power system reliability evaluations have concentr ated on the analysis of system adequacy, the ability to supply all loa ds within performance requirements. This paper deals with extending th e scope of reliability evaluations to include a probabilistic assessme nt of system security, involving considerations of transient stability and the effects of cascading sequences. For each disturbance, first-i mpact states are defined which depend on the primary effect of the dis turbance (static or dynamic problems, or no problem at all). Based on this analysis, a set of probabilistic indices is proposed to assess th e security level of the pre-disturbance state. Next, the possibility a nd consequences of secondary effects such as cascading are considered, leading to another set of indices to measure load losses due to stati c and dynamic phenomena. The approach is illustrated in a numerical ex ample.