Nearly simultaneously with the renovation of the substation, the customer also intended to build a 110 kV cable line between the Ülemiste and Lasnamäe substations in order to ensure better energy security to the region. The existing 110 kV switchgear was an AIS (air insulated switchgear). According to the procurement documentation, the new switchgear would be a GIS (gas insulated switchgear), a rather rare and more expensive solution in Estonia.

This was the first 110 kV GIS-type switchgear for the Electrical Works Department of Merko, but irrespective of the complicated secondary unit, the construction went smoothly. On the side of the secondary unit, the 110 kV switchgears were linked to Siemens 35 and 6 kV switchgears. Owing to the short distances (in-house switchgear), only 16 km of signal cables were used and connected to 11,000 terminals. The object was delivered to the customer in February 2009, and now the Ülemiste region, including Tallinn Airport, have much better energy security.

On 1 July 2021, Merko Ehitus Eesti acquired a stake in Connecto Eesti, and the Merko electrical construction business line merged with Connecto. Acting jointly under the Connecto brand makes it possible for us to offer a significantly broader range of services – in addition to the design, construction and maintenance of low, medium and high voltage electricity networks, Connecto also operates in the field of telecommunications and gas networks.

View the works performed by Connecto.