General planning of the power cable connection
During general planning, a route and construction plan for the 400 kV power cable connection, an expropriation plan for the right of use to the 400 kV cable route, an extension of the Länsisalmi substation, the Vanhakaupunki substation and a route study for transformer transport will be planned.
The aim is to complete the general planning phase in 2022 for a construction agreement and final investment decisions by the parties.
|Project type:||Underground cable|
|Project state:||General planning phase|
|Length:||About 12 km, depending on the final route selection|
Energy Authority has granted (16.5.) Fingrid Oyj a project permit for the construction of a 400 kV power line between Helsinki and Vantaa (decision Dnro 1222/040101/2022).
The tentative route of the new underground cable has been decided. Based on surveys and negotiations with authorities, the planners consider the best option to be a route through areas owned by the cities, from the Viikinranta energy block via Viikki’s fields, Hallainvuori, Ring I and the Kivikko Sports Park to Länsisalmi. The final route of the underground cable will be specified during the construction planning phase to be launched this year.
For more information:
Report on the planning phase (in Finnish)
Press release: Fingrid chooses tentative route for Helsinki’s new underground cable
The field surveys of the project will start on 28 March 2022 from the Viikinranta energy block area. The field surveys will continue until the end of June 2022.
On 25 November 2021, the National Land Survey of Finland granted Fingrid Oyj a research permit for field surveys in the areas of Helsinki and Vantaa (decision MML 72172/03). The research permit applies to all alternative cable routes.
The participation and evaluation plan for the Viikinranta energy block land use plan was available on the City of Helsinki's website until 18 June 2021.
Ramboll Finland Oy has been chosen in May 2021 as the consulting company used for the general planning.
Parviainen Arkkitehdit Oy has been chosen in April 2021 for substation architectural and structural planning.
A power cable connection will be constructed between the Länsisalmi substation and the Vanhakaupunki substation. The transmission capacity of the cable link will be approximately 1,000 MW and the project is prepared to implement a structural reservation for a double circuit.
Based on surveys and negotiations with authorities, the planners consider the best option to be a route through areas owned by the cities, from the Viikinranta energy block via Viikki’s fields, Hallainvuori, Ring I and the Kivikko Sports Park to Länsisalmi. The final route of the underground cable will be specified during the construction planning phase to be launched this year. The route length will be about 12 km, depending on the final route selection. Right of use to the cable route will be acquired through an expropriation procedure.
The cable will be installed underground and where the urban environment will limit the construction area width, a supported excavation method will be used. An example (below) of one of the cross-sections used in route planning. The cross section will be specified during the construction planning phase.
General planning includes planning of the extension of the current gas-insulated switchgear (GIS) plant of the Länsisalmi substation in Vantaa (in the images below) by at least one bay. In addition to the yard to be extended, the switchgear already has a space reservation for a double circuit.
The power cable will generate reactive power, which reduces the transmission capacity of the cable and primary equipment of substations and increases their voltage and power losses. The reactive power generated by the cable will be tentatively compensated at the Länsisalmi substation by a 400 kV reactor connected to the cable and by 20 kV reactor plants connected to the tertiaries of the transformers.
General planning includes planning of the construction of the new Vanhakaupunki 400/110/20 kV substation in Viikinmäki, Helsinki.
The switchgear will be implemented as a gas-insulated switchgear (GIS) plant and the structure is a duplex structure. The design of the switchgear is prepared for the construction of a double circuit. In addition to the GIS plant, at least one new main transformer will be acquired for the substation.
The image below illustrates the location of the Vanhakaupunki transformer substation near the Lahti Highway and the Vanhankaupunginkoski rapids. The substation will be located next to Helen Electricity Network's current Viikinmäki substation.
General planning will ensure the final transport route of the main transformer of the new Vanhakaupunki transformer substation. The transformer will be transported from Vuosaari Harbour by land to Viikinmäki. The transport route has received a preliminary decision from the Centre for Economic Development, Transport and the Environment.
A platform will be used for the transformer's road transport. Below is an illustrative example of a transformer on a platform.
tel. +358 30 395 5219
Project Manager (cable connection)
tel. +358 30 395 5274
Project Manager (substations)
tel.+358 30 395 4280
tel. +358 30 395 4297
tel. +358 30 395 5365
e-mail addresses: firstname.lastname@example.org
General planning consulting company Ramboll Finland Oy
tel.+358 50 361 7736
Architectural planning Parviainen Arkkitehdit Oy
tel.+358 50 589 6913