How we successfully re-engineered the internal layout to fit larger green equipment and high-power 1250 kVA transformers, achieving full certification in minimum time with minimal customer involvement.
How we successfully re-engineered the internal layout to fit larger green equipment and high-power 1250 kVA transformers, achieving full certification in minimum time with minimal customer involvement.
Location:
Timeline:
Client:
Scope of work:
Spatial engineering, ventilation optimization, and turnkey logistics for high-capacity, eco-friendly concrete compact substations (HEKA C).
Technical Specification:
Scaling Up Power Sustainably in an Urban Footprint
To meet strict new environmental regulations for its 2025 urban grid expansion, E.ON required high-power connection points (up to 1250 kVA) utilising exclusively SF6-free medium-voltage equipment. Deploying this in densely populated urban areas meant using concrete enclosures for design integration and durability.
However, eco-friendly switchgears naturally require significantly more physical space, and the massive 1250 kVA transformers generated higher thermal loads. E.ON faced a multi-layered challenge: scaling up power sustainably within a strict urban footprint, avoiding overheating risks, and managing the heavy logistical coordination of customer-supplied materials.
Re-Engineered Layout, Enhanced Ventilation, and Full Logistics Ownership
Harju Elekter developed an advanced, updated configuration of the HEKA C concrete substation. Our engineering teams completely reimagined the internal layout to accommodate the bulkier SF6-free RMU without expanding the station’s external footprint. To manage the thermal output of the high-power transformer, we structurally redesigned the enclosure by maximising the surface area of the ventilation grills.
To validate safety and compliance under these new constraints, we fast-tracked and successfully passed full type-tests for both Internal Arc (IAC) and temperature rise. Finally, Harju Elekter took complete operational ownership of the supply chain, coordinating all incoming material deliveries and final transport.
Certified Urban Substations Delivered On Schedule
E.ON deployed a certified, “plug-and-play” urban substation family on schedule while achieving full compliance with new environmental laws. By taking full responsibility for the complex physical redesign, rigorous type-testing, and end-to-end logistics, Harju Elekter significantly reduced the client’s administrative burden.
This allowed E.ON to focus entirely on urban grid execution rather than project management, securing a highly reliable, sustainable, and aesthetically optimised infrastructure solution for the Swedish market.
