Viktors Nikolajevs, CTEK Skillbase Manager, takes a closer look at EV load balancing and identifies which applications require a more dynamic approach.
There is growing awareness of the importance and benefits of load balancing in EV charging installations, but less so about the advantages of dynamic load balancing over static. Installers designing an EV charging system can encourage their customers who are hosting new installations to consider the plusses of load balancing in general, and dynamic in particular.
Load balancing increases the cost of the install (and, hopefully, the profit for the installer) – and even more so for dynamic – but it’s an investment for the long term that makes the system more efficient and futureproofed for expansion.
The balancing act
Common to all load balancing is a smart EV charging network that protects the main fuse by measuring the power entering the local grid and controlling the power outlets in the charging station(s).
In static load balancing, maximum total current available for all charging stations is fixed. Say there is a commercial building with a 300 A supply with ten charging points to be installed. The building’s peak demand is 100 A, so 50 A are set as a spare buffer in case of any anomalies or future improvements, and 150 A are allocated for EV charging. The ten charging points will share only the allocated 150A between themselves, depending on configuration.
If a dynamic load balancing solution is installed in that property, the overall power consumption of the property would be monitored and all of the spare capacity can be allocated to EV charging. For example, if the building is using 100 A then 200 A would be available for charging, and if the building’s consumption increases or decreases throughout the day, so will the EV charging allocation. It is an efficient system that constantly extracts as much power as possible for charging EVs.
Dynamic load balancing should be considered for larger installations, particularly where the network is part of a building’s local grid. This includes workplaces such as office buildings and factories, blocks of flats and other multi-unit residential buildings, shopping and other leisure destinations.
Such locations often have significant other power requirements, for instance for heating, air conditioning, lifts and other machinery. Connecting dynamic load balancing to the wider building management system enables real time information flow to the charging network about the variable demands elsewhere and how much power the chargers can draw. If there are renewable energy sources present, such as solar, that power input can also be communicated to the load balanced charging network.
Static balancing is suited to small charging networks, particularly those that will remain small and do not have the potential for significant expansion as EV ownership continues to grow.
For the installer, a small or medium sized project involves configuration of a controller device, which may be one of the charging stations or an additional piece of equipment, and connecting all charging stations to the internet or Local Area Network via ethernet cables or Wi-Fi. The specific requirements will vary between manufacturers.
Dynamic load balancing solutions are the only available option for domestic environments. Their main role is to protect the incoming supply fuse, so the overall load of the property should be monitored. Installation typically involves fitting Current Transformers (CTs) or an additional energy meter.
Go to the Grid
For larger installations, dynamic load balancing units such as CTEK’s Grid Central use an energy meter and CTs to inform its charge control technology which is in communication with the charging units.
This approach typically involves a separate cabinet device that contains all the load balancing technology, and in the case of Grid Central, each unit can manage up to 500 charge points. For those rare applications requiring more than 500 EV charging spaces, duplicate units can be added in as needed.
Installers will need to complete an EVCP & HP Connection Form, obtainable from the local Distribution Network Operators (DNOs), which will help them to determine if a DNO permission should be sought prior to the installation of EV charging points. For the permission to be granted, DNOs may require load balancing solutions to be installed and, in most cases, dynamic load balancing solutions are preferred.
Static load balancing is a useful addition to many smaller scale EV charging installations. But a growing number of hosts will continue to see increased need for additional EV charging on their sites, and dynamic load balancing is a good investment for them in the long term.
Get more details about CTEK’s range of EV charging solutions here