Consideration of multi-state generating unit models in composite system adequacy assessment using Monte Carlo simulation

This paper presents a Monte Carlo method for reliability evaluation of large-scale composite generation-transmission systems. The method is based on combining the basic random sampling technique with a direct analytical approach for system analysis, and the utilization of a minimization model for load curtailment. The technique is particularly suited to simulating large-scale systems and multiple states of generating units. It has been clearly demonstrated in the published literature that modelling large generating units in generating capacity adequacy assessment by simple two-state models using an equivalent or derating-adjusted forced outage rate can yield a pessimistic appraisal. Many utilities are now using multi-state models to assess capacity adequacy. The utilization of multi-state models in a composite generation and transmission study can create considerable computational difficulties when a conventional contingency enumeration approach is used. The Monte Carlo method described in this paper can be used to asess the effects of multi-state modelling in composite system adequacy assessment. The technique is illustrated by application to two test systems in order to demonstrate the effectiveness of the method.