Key Components of DC Fast Charging Stations
People new to the Electric Vehicle (EV) industry may find the DC fast charging ecosystem complex. Let's examine the equipment and utility infrastructure required for DC fast charging.
DC fast charging requires a high-voltage and high current connection to the electric grid, which is not widely available in residential areas. This is why DC fast charging stations are mostly located in public places, such as highways, shopping centers, and parking lots, where the power demand is high and suitable.
Electrical Infrastructure: Switchgear
Switchgear is a critical component of DC Fast charging infrastructure, which is composed of electrical panels with the task of receiving, distributing, and protecting the site’s power.
Let’s look at how switchgear works:
- Power Disconnect Panel: Receives 480 VAC utility power and provides power disconnect to isolate the site. Includes circuit breaker fault protection to guard the site equipment from power surges and provide power cutoff for maintenance.
- Current Transformer (CT) Cabinet: Utility-managed cabinet housing CTs (1 per phase) which measure current usage.
- Utility Meter: Displays current usage measured by CTs for utility billing.
- Distribution Panel: Divides incoming utility power into downstream circuits while providing breaker protection for each circuit.
- Distribution Panel (Low Voltage): Divides low voltage power from the transformer (6) into downstream circuits while providing breaker protection for each circuit.
- Transformer: Converts 480 VAC power to 120/240 VAC to supply lower voltage site equipment.
- Cabinet Style Switchgear: Combines #1 through #6 into a single enclosure.
Electrical Infrastructure: DC Fast Chargers
There are different types of DC fast chargers available, each with its own unique features and benefits.
ALL - IN - ONE
These are self-contained charging stations that include all the necessary components, such as the charger, power electronics, and communication systems, in a single enclosure. They are easy to install and maintain, making them ideal for small-scale applications.
POWER CABINET
These are modular charging systems that consist of separate cabinets for the charger, power electronics, and communication systems. They are designed to be scalable and can be configured to meet the specific needs of a charging site. Power cabinets are typically used for medium- to large-scale applications.
INTEGRATED BESS
These are DC fast chargers that are equipped with an integrated Battery Energy Storage System (BESS). The BESS is used to store excess energy during periods of low demand and discharge it during periods of high demand, which helps to reduce the peak power demand from the grid. This type of configuration is ideal for locations where the grid infrastructure is weak or unreliable.
Electrical Infrastructure: Utility Transformer
A DC fast charger site can recharge EVs in minutes rather than hours by delivering high power directly to the EV’s batteries. However, to provide this service, the site needs a reliable and efficient electrical infrastructure that can support the charging process.
A 480 VAC utility transformer is a type of distribution transformer that steps down the voltage from the transmission lines to the level used by the onsite electrical equipment.
A 480 VAC utility transformer is the standard voltage level for industrial and commercial applications and can provide the power required for DC fast charging stations with multiple chargers.
It is usually owned and maintained by the utility provider, who is responsible for ensuring its proper operation and safety.
The transformer will provide three-phase power to the switchgear that will be distributed throughout the site for various purposes.
A three-phase transformer can be connected in either a Delta or Wye configuration. A Wye connection is preferred for DC fast charging sites because it provides a more balanced and efficient power distribution than a delta connection.
For a closer look on how everything comes together to charge EVs read How Do EV Fast Charger Stations Work.
Putting It Into Perspective
A DC fast charging site consumes a substantial amount of energy due to its high-power output. Explore some comparisons for daily energy usage. Remember that these comparisons are approximate, and actual energy usage depends on factors like equipment efficiency, operating hours, and load profiles. Nonetheless, these examples highlight the substantial energy requirements of a DC fast charging site.
DC FAST CHARGING SITE
Charger configurations and usage can vary widely at any given DC fast charging site. To baseline our numbers, we are looking at a small site with four 150 kW chargers, operating at half capacity for 16 hours total during a 24-hour period.
RESIDENTIAL HOME
According to the U.S. Energy Information Administration (EIA), the average U.S. household consumes about 10,500 kWh of electricity per year, which translates to approximately 29 kWh per day.
C-STORE / GAS STATION
A convenience store (which includes a gas station) may have an electricity usage ranging between 15,000 - 50,000 kWh per month. So, roughly speaking, a medium size operation would consume up to 1,000 kWh per day, with up to 75% of the usage attributed to refrigeration and lighting.
NEIGHBORHOOD
Considering the average 29 kWh per day consumption of a residential home, a mid-sized neighborhood containing 100 homes would consume around 2,900 kWh per day.
DATA CENTER
At 4,000 kWh per day, this data center operates at a high energy intensity. To put it in perspective, this is equivalent to running roughly 130 servers, each drawing 30 kWh daily. Over a month, this data center would consume approximately 120,000 kWh (assuming 30 days). That’s akin to powering a small town or a large industrial facility.
FACTORY
A medium-sized factory spanning 10,000 to 20,000 square feet, equipped with energy-intensive machinery such as CNC machines, lathes, welders, forklifts, and assembly lines, could match the daily electricity consumption of a DC fast charging site.
HOW CAN NEXPHASE™ HELP?
The NexPhase™ Smart EV Switchgear is an all-in-one panel containing the entire infrastructure required between the utility service and up to four Level 3 DC fast chargers totaling 800 kW. Unlike any switchgear of its kind, the NexPhase™ features cutting-edge grid intelligence for complete EV charging station remote uptime monitoring and control.
UPTIME ASSURANCE
Provides ongoing EV charger state-of-charge and utility power monitoring, enabling CPOs to accurately pinpoint charger outages, even when charger communications are down. The remote power cycle capability helps bring chargers back online faster.
TRUCK ROLL MITIGATION
The embedded monitoring system provides remote access to real-time switchgear, utility power, and charger health data with automated alarms for condition-based maintenance planning.
DESIGN SIMPLIFIED
Eliminates the lengthy design process of traditional post-and-frame systems, which require additional costs to design, permit, and source a mixed-manufacturer panel system. NexPhase™ eliminates sourcing and supply chain delays as a single-manufacturer, turnkey solution.
INSTALLATION MADE EASY
Requires minimal on-site connections for the incoming power and outgoing charger connections, drastically reducing on-site installation time and electrician costs.
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