Taking the heat out of electric vehicle charging

Chief Investigators

Prof. John Fletcher (UNSW)

Purpose of project

The uptake of electric vehicles and fast charging facilities across Australia will present challenges and benefits to the distribution network. This requires significant investment in upgrading or installing transformers to meet the load of EV chargers. Most utilities use the nameplate rating of transformers to determine the allowable load on these assets and the need for upgrades.

One way of deferring some of the necessary investments in new network capacity is to unlock existing under-utilised capacity. A complex challenge is understanding the impact on transformer performance, particularly understanding the impacts on the thermal envelope that transformer windings will need to tolerate. This initial project aims to assess the measurement needs in the transformer to develop an understanding of the thermal response of the transformer, its windings, core and the cooling system. by improving our understanding of transformer thermal behaviour during EV fast charging sessions.

Impact of project

This project focuses on an area of emerging stress that is very likely to become a huge issue for the electrical grid. There has been very little support for distributors and research partners in going beyond the theoretical treatment of how the grid going to function. One thing that is clear is that there is embedded under-utilised capacity in existing transformers but releasing that capacity requires more detailed technical appraisal. The impact of not doing this project and not releasing this capacity will lead to

• EV customer frustration
• Significant increases in loss of supply
• The need to upgrade transformers and their local infrastructure

This project seeks to investigate whether transformers can be momentarily loaded higher than their initial nameplate rating to allow for greater Ev charging without substantially increasing transformer temperature.

It could be possible through this research to deploy more electric vehicles at existing transformers, which would indicate large potential cost savings in infrastructure deployment and reduction in embodied emissions through achieving much more throughput of EVs charging using the same original product. This coupled with dynamic connection agreements holds the potential to release significant capacity from existing infrastructure.

Project partners – industry and research