| ability to tolerate a credible event without loss of load, over-stress of system components, or deviation from specified voltage and frequency tolerances |
Figure 1 – Relationship between service reliability, system adequacy and system security
Note 1 to entry: This concept is normally applied to bulk electric systems.
Note 2 to entry: In North America, security is usually defined with reference to instability, voltage collapse and cascade tripping only.
Note 3 to entry: See also the related term "fault tolerance" (IEV 192-10-09).
Note 4 to entry: This entry was numbered 191-21-03 in IEC 60050-191:1990.