Dynamic Robust Transmission Expansion Planning

Recent breakthroughs in Transmission Network Expansion Planning (TNEP) have demonstrated that the use of robust optimization, as opposed to stochastic programming methods, renders the expansion planning problem computationally tractable for real systems. State-of-the-art robust methods treat this problem as stationary throughout the study period, with all the required investments on expansion of lines being made at the beginning of the project horizon. However, it is common knowledge that socioeconomic and environmental constraints might change considerably during the network life, such as planned increases in wind-power generation capacities, variations of environmental conditions due to climate change, or changing trends in consumption patterns, and these changes might also affect optimal capacity expansion planning. In this paper the classical stationarity assumption is dispensed with and the existing adaptive robust transmission expansion planning formulation for non-stationary approaches is expanded. The solution for this problem provides information not only about what additional lines must be installed but the construction timing during the study horizon as well. Moreover, the more evenly spread scheduling of construction, which, with the method put forward in this paper, is distributed throughout the life of the network, enables corrective measures to be taken in case the variables involved change in a manner different from that initially conceived. Numerical results from an illustrative example and the IEEE 118-bus system are presented and discussed, demonstrating the benefits of this non-stationary approach with respect to classical methods.