Performance assessment of distribution transformers under EV loading in the residential sector

This research analyzes the impact of EV charging at residential sector with conventional distribution transformers of 200 and 375 kVA ratings in terms of power quality factors. Subsequently, the characteristic comparative performance assessment of Conventional Cold-Rolled Grain-Oriented electrical steel (CRGO) and Amorphous Core Transformers in terms of core losses, oil temperature, voltage and current measurements, no load and full load conditions were tested for 8 h. The objective is to analyze amorphous testing as replacement of CRGO for EV residential charging. It was found that during 100% loading with 200 kVA transformer, current reaches to 504.9 Amps and transformer loading reaches to 149%. On the other hand, the 375 kVA transformer loading was 96% during the full load. While analyzing the characteristic performance comparison between Amorphous and CRGO, it was found that Amorphous out performs compared to the CRGO transformers where the no load losses was 73% and load losses were 23% lesser than the CRGO transformers. On the other hand, the oil temperature remained 25% lower proving that amorphous transformers could be a better replacement for CRGO transformers.