Dynamic model for long-term expansion planning studies of power transmission systems: the Ortie model

Abstract With regard to its complexity, the long-term expansion planning problem of a power transmission system cannot be tackled without making some broad assumptions. In the present study, it is assumed that the investment variables are continuous variables and that the flow on the transmission system complies with Kirchhoff's current law only. Moreover, only the forced outage rates on thermal generation units are taken into account, whereas all other uncertainties are ignored. The problem to be solved may be defined in the following way: if the increase in demand and the structure and site of the generators are known, the maximum transfer limits of the network at each point of time of the period studied can be determined so as to minimize the investment, operation and reliability costs. Using certain assumptions, the problem is solved by linear programming techniques. The special structure of the constraint matrix makes it possible to apply two methods for solving large-scale problems: a column generation technique with maximal flow problems as subproblems, and a partitioning technique of the basis matrix.