Expansion planning of medium voltage distribution networks

The paper proposes a new methodology for optimal planning of medium voltage distribution networks. The overall model is presented as a two-stage optimization model, where the first stage deals with the investment part and the second stage focuses on the operation part. The novelty of the proposed model is demonstrated through the explicit incorporation of network security constraints in the mathematical model, in line with the UK planning standards, while taking into consideration different operating regimes with changing load and generation profiles, integration of new distributed generation units, construction of circuits on new corridors and optimal network reconfiguration. The highly complex mixed-integer nonlinear optimization model is applied to a few practical medium-voltage test systems of up to 120 nodes using a dedicated commercial software package. Some of the characteristics results are examined and highlighted in this paper. Additionally, sensitivity analyses are done to determine critical parameters affecting the development and performance of medium voltage distribution networks.