Caption: Compact pre-fabricated substation with dry transformer and RMU switchgear, enabling high-power EV charging network expansion along major highway corridors in Sweden.
Technical Specifications
Equipment:
- 1 unit of 11kV Ring Main Unit (RMU)
- 1 unit of 1600kVA 3-phase dry-type transformer
- Integrated EV charging grid connection and protection panel
Core Parameters:
- RMU: 11kV rated voltage, SF6 insulation, 1 incoming + 1 transformer feeder + 1 spare feeder configuration, equipped with protection relay and energy metering.
- Transformer:** 11/0.4 kV voltage conversion, Dyn11 vector group, ANAN cooling, designed for 50Hz operation.
- Shared Feature:** Nordic climate adaptation for low temperatures and high humidity cycling.
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Key Features
Modular & Scalable Charging Infrastructure:
The RMU provides a reliable grid connection point for multiple high-power charging dispensers (up to 350 kW per port). The design allows for straightforward capacity expansion by adding parallel transformer units or upgrading to higher ratings.
High Efficiency & Low Environmental Impact:
Dry-type transformer with Class F insulation and low-loss core design minimizes operational energy waste and eliminates oil leakage risk. Suitable for indoor and outdoor installation without additional fire protection systems.
Cold Climate Resilience:
All enclosures rated IP54 for outdoor installation; transformer designed to operate reliably at ambient temperatures as low as –30°C. Heating elements integrated in RMU and transformer compartments to prevent condensation.
Smart Grid Ready & Safe Operation:
RMU includes remote monitoring interface (IEC 61850 ready), fault indicators, and earthing safety interlock. Transformer equipped with temperature monitoring and alarm contacts for predictive maintenance.
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Project Execution
Prefabricated & Fast Deployment:
Fully assembled and tested substation module delivered to site, reducing installation time by 60% and enabling rapid integration into existing highway service station layouts.
Phased Roll-Out Support:
Deployment aligned with the national EV charging corridor plan, allowing staggered activation of charging stations along the E4 and E20 highways without grid downtime.
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Operational Results
Grid Stability under High Dynamic Loads:
Substation successfully supports simultaneous high-power charging of multiple EVs, with minimal voltage fluctuation thanks to low-impedance transformer design and fast RMU protection response.
Energy Efficiency in Continuous Operation:
Dry transformer no-load and load losses meet IEC 60076-11 Class B efficiency levels, reducing operating costs for charging network operators.
Durability in Harsh Climate:
Equipment designed for >25-year service life under Nordic weather conditions, with minimal maintenance needs and high resistance to thermal cycling and moisture.
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Certifications & Standards
- Compliant with IEC 62271-105 (RMU), IEC 60076-11 (dry transformer), and Swedish SS-EN standards.
- SF6 handling according to EU F-gas regulations.
- Documentation provided in English and Swedish, including type test reports and commissioning protocols.
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Client Benefits
Reliable High-Power Charging Availability:
Ensures consistent power delivery essential for commercial EV fleet and long-distance travelers, enhancing user satisfaction and network uptime.
Future-Proof Design for Grid Expansion:
Modular structure allows easy capacity increase to support next-generation charging technologies and higher EV adoption rates.
Reduced Lifetime Costs:
High efficiency lowers electricity losses, while dry-type transformer reduces fire safety costs and environmental compliance burdens. Prefabrication cut civil works and commissioning expenses significantly.
