Switchgear and substations

Kolviðarhóll substation

Hellisheiði - southern Iceland

  • Tengivirki-Kolvidarholi

Verkís services was project planning, design memoranda, tender documents, tender design, contracting and design supervision, design review of contractors detail design, final design of electrical installations in the building and overall layout of the substation and all electrical equipment.

 Sizes: 220 kV
 Project time:  2003 - 2008

Project overview:
The substation is located near Hellisheiði geothermal plant, about 25 km east of Reykjavík. The substation facilitates the transmission of electricity from the power station into the 220 kV grid via two transmission lines, extendible by three transmission lines. Five 45 MW geothermal generating units are individually connected to the substation, extendible by three units.

The substation is located close to the Hellisheiði geothermal power station and is influenced by frequent earthquakes and H2S pollution in the area. The substation building's ventilation system is equipped with incoming air H2S filters to prevent corrosion in copper and other metals. The fully built substation will be one of the largest in Iceland and an important link in the transmission grid.

The substation equipment is housed in a concrete building on two floors with the switchgear and control- and protection equipment on the ground floor and auxiliary equipment, storage rooms and HV cable corridor on the basement floor. The 245 kV switchgear is connected to five unit transformers (extendable to eight) in the Hellisheiði power station by power underground cables, approximately 1.000 m long. Two 245 kV transmission lines connect the substation to the national grid with the possibility to add up to three transmission line connections.

The switchgear is of the SF6 gas insulated indoor type, suitable for direct connection with SF6/air bushings to transmission lines and XLPE cable connections. Due to the size and importance of the substation further extension of the switchgear will include disconnectors in the main busbars. They will make it possible to keep half of the substation in operation in case of busbar fault or extensions. The substation is equipped with a redundant modern control and protection system and is normally remotely controlled and monitored from a dispatch centre in Reykjavík. The substation auxiliaries include double DC systems and both 11 kV and 400 V auxiliary supply from the power station.

The substation building is equipped with low voltage installations, lighting and emergency lighting. Important feature is the modern fire alarm system and the intrusion and access control system.