The Imbalance-Induced Resistive Heating Profiles Analysis for Low Voltage Transformers

Phase imbalance in the UK and European low voltage (415V, LV) distribution networks is a widely acknowledged issue. For LV transformers (11 kV/0.415 kV), phase imbalance causes extra energy losses on transformer windings. These extra energy losses induce the imbalance-induced resistive heating, which then causes the increase of LV transformers' winding temperature. A key barrier for understanding the general picture of imbalance-induced resistance heating is the absence of LV transformers' time series loading data, i.e. UK has 900,000 LV transformer, but most of them are not monitored. To address this challenge, a data-driven approach is proposed. It finds representative clusters of the imbalance-induced resistive heating profiles, leverage the data from only 800 LV transformers. Through an extensive case study, the representative imbalance-induced resistive heating profiles are given by cumulative density functions. The case study also reveals that up to 50% resistive heating is produced by the imbalance-induced resistive heating.