Probabilistic reliability assessment in operation planning

The Brazilian power grid has traditionally been designed and operated using a set of deterministic reliability criteria. They have played an important role in the design and operation of the Brazilian bulk power system for decades. However, they tend to use available resources less optimally and over-book facilities in the context of transmissions capacity. With regard to the approval of scheduled maintenance of transmission equipment on the basic grid, the main deterministic criterion adopted by the Brazilian Independent System Operator (ISO) is the n − 2 criterion. The current article proposes replacement of the deterministic n − 2 criterion by a probabilistic criterion to allow for more scheduled maintenance during medium load workdays, without significantly increasing the risk level of the system. The expected result of implementing our recommended criterion is a reduction in operations and maintenance costs, which should in turn reduce the electricity rates paid by end users.