Transmission constrained maintenance scheduling of generating units: a stochastic programming approach

Abstract

This paper presents a new methodology for maintenance scheduling that takes into account inter-area transfer limitations and stochastic reliability constraints. The optimization model is based on the Benders decomposition technique. The objective of this model is to determine a minimum cost maintenance schedule, subject to technological and system reliability constraints. The model may be used also to assess the adequacy of existing transmission limits under a given set of planned outages of generating units. Case studies with a realistic three-area power system are presented and discussed. INTRODUCTIONMaintenance scheduling of generating units is an important problem related to power system planning and operation. This problem is characterized not only by its high dimensionality, but also by its complexity, even when transmission constraints are not considered. The overall generation maintenance scheduling problem may be approached from three hierarchical levels: power plant, utility and interconnected system. From the power plant point of view, the scheduling problem objective may be cast in tenns of determination of the most adequate maintenance interval for each generating unit, in order to attain (or keep) a satisfactory equipment availability level. The constraints in this level are associated to crew and repair shop availability, technological aspects, ageing, and so on. At the utility (or area) level, the objective is to maximize generation availability subject to the same plant constraints, plus additional constraints related to area load supply and interchange contracts. Finally, at the pool (or multi-area) level, the problem solution must include, besides plant and area constraints, additional constraints related to interchange capability limits, pool reliability criteria and mutual assistance practices, load diversity and seasonality, and so on. These hierarchical levels are symbolically depicted in Figure 1.

Short-Term Transmission Maintenance Scheduling Based on the Benders Decomposition

“…( 1 6 ) Because the variation of the maintenance cost is not obvious with marginal change (as 1 MW in [6], [7] ) in the line capacity, we cannot generate the proper feasible cut to restrict the objective function. So we adopt N-1 criterion to obtain the multiplier of feasible cuts at each period t .The improved equations are as follows: …”

“…Reference [5] and [6] study on the integrated generation and transmission maintenance and arrange the scheduling by a combined method. Although the electric network topology and transmission capacity are sometimes used as the network constraints in generation maintenance, the effect of transmission line fault is usually ignored in [7]- [8].…”

A New Approach for Generator Maintenance Scheduling in Deregulated Power Systems

“…Decomposition approaches [17][18][19] were presented to handle the coupled constraints through decomposing the problem into a master problem and a series of operating subproblems. However, the decomposition approach is subject to the trade-off relationship between the iteration number and the solution quality.…”

Security-Constrained Generation and Transmission Outage Scheduling With Uncertainties

“…The study in [4]- [7] focused on generation and transmission maintenance and their coordination. However, the subject of transmission security in restructured power systems was not considered.…”