Construction of 400KV power cable in Helsinki starts in spring

Construction of a new underground main grid cable link in Helsinki will begin this spring, said Finnish national electricity transmission grid operator Fingrid in a press release on Monday.

The project, run jointly by the City of Helsinki, Helen Electricity Network and Fingrid, will respond to growing electricity consumption in the Helsinki Metropolitan Area and promote the green transition.

Construction began on the link from Vaarala in Vantaa to Viikki in Helsinki in December with the clearing of trees from the cable route and worksite areas. The project is proceeding on schedule and is due for completion in 2026. 

In 2023, the City of Helsinki, Helen Electricity Network and Fingrid signed a partnership agreement to build a 400-kilovolt electricity transmission link in Helsinki.

The National Land Survey of Finland has issued an expropriation permit decision for the cable route. The cable, construction of the cable route, and substation procurement processes progressed in autumn 2023.

“The project has proceeded on schedule and within the budget and in a good spirit of cooperation between the parties, authorities and stakeholders,” said Risto Ryynänen, Project Director of Fingrid.

The largest contractors and suppliers are Hitachi Energy Finland Oy for substations, Tamini Trasformatori S.r.l. (an Italian company) for power transformers, Hyosung Heavy Industries Corporation (a South Korean company) for 400-kilovolt reactors, GRK Finland Ltd and Lännen Alituspalvelu Oy for construction of the cable route, and Demirer Kablo (a Turkish company) for 400-kilovolt cables.

In addition, Architecture Office Olla Ltd and A-Insinöörit Suunnittelu Oy are responsible for the construction design of the Vanhakaupunki and Länsisalmi substations. Ramboll Finland Ltd will continue as the building consultant and designer of the cable route.

When completed, the 400-kilovolt cable link will run from the Länsisalmi substation in Vantaa to the new Vanhakaupunki substation in the energy block in Viikinranta, Helsinki.

“Investments in the electricity grid are essential enablers of the green transition. This is an important project for Helen Electricity Network, as it will allow us to connect new customers to our network. Our Viikinmäki substation project will pave the way for connecting to Fingrid’s 400-kilovolt substation in Vanhakaupunki in 2026,” said Markku Hyvärinen, Director of Business Development at Helen Electricity Network.

The new cable link will also enable alterations to the electricity network for the construction of the Western Boulevard City, a project on the other side of Helsinki, around the Vihdintie and Huopalahdentie roads.

Once the network is reinforced, the high-voltage 110-kilovolt overhead lines near Vihdintie and Huopalahdentie can be moved underground. This will free up land for infill construction.

“The underground cable we are building now is mainly located under green areas and in the street area of Viikinranta, where new buildings are planned. From the City of Helsinki’s perspective, the project is important for the green energy transition and the development of the urban structure,” said Pekka Tirkkonen, Specialist in the Helsinki Urban Environment Division.

In April 2022, Fingrid and its partners disclosed the planning to build a new 400 kilovolt underground power cable in Helsinki.