Cable power flow : pushing the limits on existing installation standards for distributed EV charging systems : effects on heat and power transfer through installation and environmental changes

Abstract

The increasing use of electricity to power the world has had many challenges, from generation all the way to the delivery of the electron. Possibly the biggest and most challenging sector to electrify is the mobility sector due to high demands on range and, most importantly, charging times. While more power can be supplied with larger, more resilient cables, there is a point where it becomes unfeasible, unsustainable and not economically viable to increase the conductor size. This study examines how heat is dissipated from the cables to the surface and aims to push the boundaries and determine the limits of existing cable installations.

Steady-state and transient simulations are performed in Ansys Fluent, testing a wide range of installation and environmental changes, aiming to aid electrical distribution design and thermal optimization, while also acknowledging the effects of different soil properties during steady-state and transient formulations. Additionally, real site utilization data was used to simulate and analyse the behaviour of a busy electric vehicle (EV) charging site as well as to determine the maximum system temperature at peak loading conditions.

The results indicate that wiring standards significantly underestimate a cable’s true current carrying capacity when in a bundle encased inside a conduit buried underground, with larger variances in derating factors visible in higher conductivity soils. It also separates high-power EV charging behaviour away from typical electrical connections, identifying the truly unsteady nature of EV charging.