This article presents a novel numerical approach aimed at finding a distribution network expansion plan that prevents future congestion and voltage issues. Forecasted duration and intensity of thermal and voltage violation events are used to determine a pool of potential candidates for infrastructure (i.e., line/cable) upgrade, voltage regulator, and energy storage system installations. This is complemented with an algorithm to obtain the minimum-cost list of these candidates that solves all constraint violation events using binary linear programming. This approach is validated using the modified IEEE 33-bus network and a real 1171-bus feeder in the West of Ireland through numerous high-resolution quasi-static time series simulations. Three pools of candidates and three cost projections were considered to explore the method’s sensitivity to different scenarios. Results show that the proposed methodology is a versatile tool for designers, planners and policymakers. The methodology can ensure that the investment plan solves all forecasted violation events. Nevertheless, we show that accepting a marginal degree of violations may be acceptable and would significantly reduce investment costs.

Power distribution networks are experiencing large deployment of behind-the-meter distributed generation and storage along with electrified transport and heat, requiring fundamental changes in planning and operation. Synthetic representative networks may not be sufficient to fully address the needs of researchers, operators and decision-makers. There are increasing efforts to directly model large-scale real networks and conduct detailed analysis beyond conventional practices. This paper presents a large-scale medium voltage (MV)-low voltage (LV) integrated network model building, scenario determination and analysis approach for distribution networks. Data with different formats from several databases were used in model building. The model is validated using benchmark scenarios based on historical network measurements from the field. In collaboration with the national distribution system operator in Ireland (ESB Networks), a pilot study was conducted for a rural network in the Southwest of Ireland, highlighting possible challenges and offering suitable solutions for country-scale implementation.