Empirical Design Method for Distribution Transformer Utilization Optimization

The increasing penetration of electric vehicles and distributed generation into distribution networks are giving rise to higher, more volatile, and bi-directional energy flows through distribution transformers (DTs). To minimize future capital expenditure, improved DT design approaches are required. Therefore, a novel DT design approach based on a new paradigm of “designing for maximum utilization” is proposed. It incorporates manufacturer and customer-sourced empirical data to achieve a desired DT retirement age and utilization rate, and allows for transient operation beyond DT nameplate rating through accurately accounting for thermal inertia. The novelty of the proposed approach derives from not only a new notion of designing for maximum utilization, but also allowing for the fact that winding insulation may not be the most critical factor affecting a DT's lifetime. Using the proposed approach, DT capital expenditure and utilization constraints can be optimized at a planning stage. The algorithm is applied and validated..