The use of electric vehicles, or EVs, as a general source of transport, is growing rapidly. In 2023 over 87,000 EVs were sold in Australia, representing a growth of 121% on the previous year. EVs are noted for their sustainability contribution and low running cost and are considered a viable means of transport by many people for private use, in mass transport utilising EV powered buses, and semi-trailer prime movers are going beyond prototype electric models to feasible options for large scale transport.

The increasing adoption of EVs has seen a rapid expansion of the private and public charging networks. The connection of charging infrastructure with power grids has seen electric mobility forming an important part of the energy revolution.  

The ‘chicken and egg’ scenario saw apprehension of many people wanting the infrastructure to be installed before they commit to an EV, and the charging network operators needing to see greater consumer demand to develop their business case to commit to charging developments. These opposing views are coming together as vehicle demand has increased. Car manufacturers are releasing new desirable models, and the charging infrastructure availability is increasing so the previous concerns on vehicle range anxiety are easing. 

For many private users, the major source of charging will be at home using low-capacity overnight charging. On longer journeys the destination charge options have become more widespread. 

We know that all electrical networks need to have appropriate, well designed protection systems. Our traditional approach is to provide protection against short-circuit and thermal overcurrent faults in accordance with AS/NZS 3000 requirements. Considering the value of our EV charging equipment, and our reliance on the chargers to maintain our transportation needs, we should consider protection against another threat, that of lightning and surge impulses and overvoltages. These effects can dramatically affect charging equipment, shutting down the entire charging system and potentially damaging a connected vehicle. In some jurisdictions around the world, local standards stipulate surge protection must be fitted to protect charging equipment, but this is not the case in Australia yet. 

The Australian Bureau of Meteorology reports there are up to 8 million lightning strikes per day worldwide, or about 44 strikes per second. In many parts of Australia, the official lightning risk is considered reasonably low, but recent weather events have recorded high level of lightning strikes across Australia, covering even those low-risk areas.

A research study from the US has told us that for every 1oC of global warming there is a 12% increase in lightning activity. The CSIRO State of the Climate Report 2022 indicates the average temperature in Australia has increased by around 1oC between 2000 and 2020. This supports the view that these lightning events are becoming more and more prevalent. 

So how does this affect EV chargers? A direct lightning strike on the electrical network can create a significant impulse on the power supply that can pass straight through conventional circuit protection and damage electronic components. Indirect lightning strikes, those that occur near the electrical network, also find their way to equipment via the earthing system.  The impulses can raise the potential of the earth momentarily to dangerous levels for equipment. 

There is also unseen damage. While surges due to lightning events can be obvious and often dramatic, surges can be lower-level transient effects like grid switching by the supply authorities and switching of large loads at a site. These switching events are a silent killer and can cause deterioration of electrical and electronic components over time, leading to premature failures. 

When we consider an EV charging scenario, these damaging surges can flow through the power network and into the charger. If the charger is involved in a charge session with a vehicle at the time, then there is a link to the car itself. A surge can potentially damage charging equipment, not only the charger, but also the vehicle-based equipment such as the onboard charge controller or battery, which could compromise personal safety and the vehicle electronics.  

Often EV charging infrastructure can be outdoor and quite exposed, so the need to protect people and assets is increasingly important.

The solutions are simple and quite inexpensive compared to the asset we are protecting. 

In some cases, the public charging networks utilize fast chargers and ultra-fast chargers, and many of these have surge protection fitted internally. 

This is generally not the case in smaller capacity chargers, where the application of surge protection devices is generally outside of the charger, and the responsibility of the owner. 

Some chargers, large and small, may be fitted with surge protection supplied inside the charger cabinet, which often has a moderate capacity, if it exists at all. In these cases, we need to consider external surge protection as a backup for the charger, to protect the charger, the vehicle, and the user.

Often the capacity of the surge protection supplied does not suit the location of the site, so a proper risk assessment according to AS 1768:2021 should be completed to ensure appropriate protection is available. 

• If your equipment is more than 10 metres from your surge protection, consider additional protection.  
• Always put surge protection close to what you are protecting. 
• As an example, protect your main switchboard, then your distribution board and so on until the charger.

In larger sites there can also be data communications to the charging infrastructure for load sharing and reporting. This can also be affected by surges which can disrupt networks and cause significant failures of expensive equipment.

Fortunately, we have a variety of solutions that offer protection against these threats. The solutions are low cost and easily implemented, to guard these valuable assets against damage. 

IPD offers a comprehensive range of solutions from leading surge protection manufacturers Dehn and Novaris, coupled with expert application assistance to ensure optimal site protection and reliability. 

For more information, contact IPD at 1300 556 601 or visit our website.