Abstract
This paper presents the multistage distribution network planning problem, utilizing conventional and non-conventional expansion measures. Here, conventional network expansions, i.e. transformers and lines installations, compete with load flexibility contracting. The proposed multistage planning methodology aims at minimizing the net present value of all investment and operational costs, while annuity calculations are used to make technologies with different characteristics comparable. A novel combination of the pseudo-dynamic planning approach called forward fill-in with a single-stage planning approach that utilizes load flexibility is developed. The single-stage distribution network planning model is based on the Tabu Search metaheuristic, which has proven to be scalable for realistic large-scale networks. In a case study, the multistage model is applied to a two-stage planning problem.The results show clearly that the proposed multistage methodology is useful for planning studies. In contrast to single-stage methodologies, the multistage methodology not only allows to account for the time value of money, allowing to analyze savings due to network investment deferrals. But it also allows to demonstrate the value of flexibility contracting in distribution network planning. In the case study, flexibility contracting at a cost of 10 €kW per year results in total cost savings of 15.68 .
