Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Reliability calculations for interdependent plant outages. Final report

Technical Report ·
OSTI ID:6317855
The present methods of calculating a generating system loss-of-load probability (LOLP) assume that generator forced outages are independent; that is, the forced-outage rate of 1 unit is not a function of the status of other units. In reality, the outages of generating units are not independent events, but they are a function of generator usage and maintenance schedules. The purpose of this study was to show the effects of removing the assumption of independency among unit forced outages of an electric generating system. This assumption was negated by two procedures: (a) the unit forced-outage rates were made dependent on the health of the system; that is, the number of generating-unit outages on the system and (b) the number of repair crews was constrained so that some units might have to wait for repair. Solution methods were developed to calculate system LOLP for the cases of a single change and multiple changes in forced-outage rates of generating units. Procedures were also developed for calculating the system LOLP for the case of a limited number of repair crews at a particular generating station. The study results of a hypothetical test system with 10 generating units demonstrated the degradation of forced-outage rates for individual units when unit dependencies and maintenance schedules were considered. The study pointed out the data problems and difficulties in calculating dependent forced-outage rates of generating units.
Research Organization:
Energy Management Associates, Inc., Santa Clara, CA (USA)
OSTI ID:
6317855
Report Number(s):
EPRI-EL-3669; ON: TI85920128
Country of Publication:
United States
Language:
English