Probability studies of interconnection capacity

The problem investigated is the mathematical determination of the flow through a channel of finite capacity when the supplies and demands at each end are described in terms of probability distributions. Supply sources consist of generators of different sizes scattered throughout the system, their outages being treated as independent random events. Uncertainties in demand relate to errors of load estimates prepared several years earlier, on which plans are based. Risk of failure to meet demands is increased whenever reserve generating capacity cannot be utilised because of transmission restrictions. By dividing a power system into two arbitrary regions A and B, the risks are calculated of incurring unsatisfied demands when interconnection capacity across the interface has been absorbed. Because errors in demand estimates for each part of the system are not independent, the unbalances between generation and demand in A and B are correlated, and this has an effect on the interconnection requirement. Planning curves are given showing interconnection capacity at different risk levels. A cost analysis is carried out to obtain the optimum allocation of resources between interconnection and generation.