Frequency and Duration Methods for Power System Reliability Calculation Part IV: Models for Multiple Boiler-Turbines and for Partial Outage States

The presentation of a unified method for power system reliability calculations is continued. Techniques are presented for determining the availabilities and frequencies of occurence of the capacity states which may arise with multiple boiler-turbines or with recognition of the forced partial outage states of unit-connected boiler-turbines. A comparison is offered of the effects of lumping partial capacity outages into equivalent total forced outages upon generation system reliability predictions. Several numerical examples are shown to illustrate the methods developed. For several examples studied, simple equivalents with a reduced number of states were developed which were found to be excellent approximations to the complete Markov chain description of the stochastic processes involved.