Power Configuration for Large‑Scale EV Charging Station Projects
1. Rising Demand for Supporting Power‑Distribution Equipment for EV Charging Projects With fast development of electric vehicles across the globe, governments invest heavily in public charging stations, highway charging lots and commercial EV‑charging parks. A single high‑power DC charger can consume 60kW‑240kW power. When dozens of chargers work together, they put high loads on local power‑grid systems.
Only installing charging piles is far from enough. Matching medium‑voltage switchgear, RMU ring‑main‑units, distribution transformers and compact substations are essential parts for stable operation of EV‑charging stations. Many project investors make mistakes in power‑equipment matching at the early design phase.
2. Standard Power‑Distribution Layout of EV‑Charging Stations
2.1 Medium‑voltage incoming section (11kV‑33kV) The high‑voltage power from public grid first enters RMU ring‑main‑units. RMU acts as power distribution and protection equipment. When faults happen on one power‑supply branch, RMU can cut off the faulty line without affecting other charging‑pile groups. For large‑scale charging‑parks, 33‑kV SF6‑insulated RMU is widely adopted because of its compact size and low‑maintenance features.
2.2 Voltage reduction section by distribution transformers
After RMU, high‑voltage power flows into distribution transformers. Transformers step‑down 11kV‑33kV high voltage to 400‑V low voltage for charging piles. Dry‑type transformers are more popular for indoor charging‑stations for safety reasons. For outdoor charging lots, oil‑immersed transformers with compact‑substation packages become the mainstream choice.
2.3 Low‑voltage outgoing section
Low‑voltage switchgears (MNS/GGD type) distribute 400‑V power to each DC‑fast‑charger and manage overload and short‑circuit protection for individual charging piles.
3. Important Design Principles for EV‑Charging‑Station Power Systems
3.1 Reserve extra capacity for future expansion
The number of charging piles often increases year‑by‑year. We advise clients to reserve about 30‑40% extra transformer and switchgear capacity. If you build 20 charging piles at present, your power‑equipment should support 30 piles in the future.
3.2 Load‑balance design
When all high‑power chargers start working at rush hours, the sudden high‑load will cause grid‑voltage fluctuation. Our engineers can design load‑sharing control systems, which stagger peak‑working time for different charging‑pile groups.
3.3 Compact‑substation integrated solution
For highway‑side charging stations, there is not enough room to build separate power‑distribution rooms. The prefabricated compact‑substation integrates RMU, transformer and low‑voltage switchgear inside one cabinet. It can greatly shorten construction periods and save land space.
4. Custom‑Demands from Global EV‑Charging‑Project Clients
Overseas customers often have personalized requirements:
1. Intelligent monitoring system to observe real‑time power‑consumption data of each charger;
2. Equipment works under extreme‑temperature conditions from ‑20℃ to +55℃;
3. All electrical components comply with IEC standards and get CE certificates.
Ningyu Power has finished many EV‑charging‑station power‑support projects for clients in Southeast Asia, the Middle East and Africa. We supply complete sets including RMU, transformers, MV‑LV switchgear and compact substations.
