• • • ELECTRIC VEHICLES • • •
The EV dream – How to make it reality By Tom Mennell, technical standards manager, Power Systems UK&I at Schneider Electric
he importance of electric vehicles (EVs) is growing as societies strive to become carbon neutral. According to a recent prediction by the International Energy Agency, sales of electric and hybrid vehicles are expected to reach 17 million this year, an increase of over 20 per cent from 2023. This follows new government legislation at the start of the year to drive EV adoption. However, the EV dream will never become a reality if we do not have the infrastructure in place to support it. Whilst many EVs today are charged from homes, using a domestic electricity supply, it is also essential that our public spaces are future proofed for the EV revolution. We must install reliable electric chargers in vast quantities across the UK. And in order to do so, especially outside the home, a new approach to electricity management, which prioritises outdoor low-voltage assemblies, is needed.
T Outdoor low voltage assemblies
– the key to wider adoption For electric car charger supplies to be controlled and safeguarded, low-voltage assemblies are essential. Since the majority of EV charging stations will be located in public areas, outdoor low-voltage assemblies may be more advantageous than traditional indoor assemblies. One benefit that they offer is that they require less space as they don’t need to be placed inside buildings or have extra enclosures or housings. As a result, the assembly can be placed considerably closer to the chargers.
In addition to this, installation can be conducted much faster because the assembly is delivered as
a single unit. This usually also means that both initial and lifetime cost of the product are reduced. Because outdoor assemblies can be located much closer to the point of load, the length and size of cable runs can be substantially reduced. As shorter cable runs result in lower losses, operational costs can also be significantly lowered. However, when it comes to EVs, the charging application is much more demanding than it usually is for low-voltage assemblies. This can present some unique challenges.
Obstacles and how to overcome them
A major obstacle with EV charging stations is that conventional electrical systems aren’t made to manage many circuits running at maximum capacity at the same time. For EV charging stations, this feature is essential, especially during summertime high demand with high temperatures. Higher-rated components that can withstand high temperatures and constant load are required to address this, guaranteeing the system’s dependability and safety even during prolonged usage.
Another critical issue is ensuring safe earth leakage protection. Most EV chargers require a residual current device (RCD) to protect against electric shocks, as mandated by safety standards. However, EV chargers produce small direct currents (DC) that can interfere with standard RCDs. The solution is to use Type B RCDs, which are better at handling these small DC currents, ensuring reliable protection for users.
Additionally, safeguarding against electrical malfunctions is crucial, especially in the event of an electricity supply fault, like a broken open protected neutral (PEN) wire. These errors increase the possibility of electric shock and equipment damage. Accidents can be avoided by installing technologies that identify these flaws and isolate the problematic area of the network automatically. For example, certain products on the market offer complete safety by cutting off the power supply in the event of such malfunctions. Electrical system performance can be impacted by high temperatures, particularly during periods when EV charging is at its highest. This is why it is important to test assemblies in simulated conditions, to make sure they can withstand the heat. Through testing, the system’s performance and design are improved to endure high temperatures and preserve dependability. As most assemblies controlling electric vehicle supplies are located in areas accessible to the general public, consideration should be given to safety on those very rare occasions that there is an arcing fault within the assembly. Assemblies used in these applications should be internal arc fault tested to demonstrate that any arc will be contained within the assembly or directed to a safe area.
It’s critical to make sure the infrastructure for EV chargers resists corrosion because they need to last for a long time, especially in harsh environments. Using robust materials, such as pre-galvanised mild steel with superior paint finishes that have a 25-year lifespan, is a cost- effective approach. This method is less expensive than stainless steel and offers superior protection.
24 ELECTRICAL ENGINEERING • NOVEMBER 2024
electricalengineeringmagazine.co.uk
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