Kolvidrholl Substation, Iceland

Client: Landsnet
Project: Construction of substation
Located just south of the Hellisheiði Geothermal Power Plant about 30 km east of Reykjavik, the Kolvidarholl substation serves the plant and is connected to it by underground high voltage cables. 
The building consists of a 362 m² switchgear hall for 245 kV SF6 high voltage equipment and 180 m² of control and service rooms, as well a 550 m² basement area housing a variety of control equipment, and the air conditioning system and ducts.
The structural system consists mainly of concrete cast in-place, apart from the roof over the switchgear hall which consists of precast concrete hollow core slabs with concrete topping. The structure is founded on compacted gravel and is insulated on the inside, and is partly covered outside with aluminium cladding, in order to achieve a similar appearance to other structures in the vicinity.
An overpressure is maintained in the building and the HVAC system contains filters to prevent H2S infiltration and the possible corrosion of sensitive equipment. As well as safety for the employees, the fire engineering design aims to provide adequate protection against fire and smoke for delicate equipment and sensitive power production.
The building is located directly below the Burfellslina 2 245 kV transmission line, which is connected to the building and can be by-passed over it if necessary.
The substation can be readily extended in future to add further high-voltage equipment and transmission lines if required.
Construction work began in June 2005 and was completed in September 2006. 
EFLA scope:

• Structural design

• Plumbing design

• HVAC design

• Fire safety design

• Project supervision