Ensto goes underground – power distribution for metro in Finland

The metro system in the Finnish capital region is expanding in Espoo. The second phase of the western metro expansion will bring five new stations and a new underground depot. The new seven-kilometre rail line will have over 50 km of medium voltage underground cable installed, which will serve as the main distribution network for the railway section. A consortium between GRK Rail and Eurolaite will be in charge of the main power distribution in the project. Ensto provided the medium voltage underground cable accessories for the construction project, and organised training for the electricians on underground cable terminations.

The Helsinki Metro is the northernmost metro system in the world. The 35-km-long metro line links Helsinki city centre to the city’s eastern districts. With the new West Metro extension, it will reach the continuously growing southern Espoo area. The new line will run underground in two parallel 21-km-long tunnels. The construction work is currently under way at the new metro stations and depot, and on the rail line. The construction phase takes place between 2019 and 2021, and the deployment phase in 2022–2023. The new seven-kilometre rail line will have over 50 km of medium voltage underground cabling installed, which will serve as the main distribution network for the Matinkylä-Kivenlahti railway section.

The contract for GRK Rail, the company responsible for the main power distribution, covers medium voltage switchgear, distribution transformers and support systems, and the required cabling, including equipment, materials and installations.

‘The second phase of the West Metro project is proceeding well and to schedule. It involves building a medium voltage network in the tunnel. We are currently working on installing cables, terminations and joints. Ensto’s products were selected because they are the most suitable for us’, says Lucas Holm, project manager from GRK Rail.

Operations defined by quality

Ensto’s products are the result of long-standing product development and testing in the company’s accredited laboratory in Porvoo, Finland. The products are designed to be reliable and their features have been thoroughly type-tested.  ‘Ensto’s products have received particular praise for their ease of installation and long service life. Using high-quality products in the distribution network creates the basis for its reliable operation’, summarises Marko Kylliäinen, sales manager at Ensto Finland.

Ensto provided the underground cable accessories for the West Metro’s medium voltage cable. Class A conduits have been built along the edges of the metro tunnel where the cables run throughout the entire line. The cables are connected together using hybrid joints and connection to the substation's switchgear or transformer is done using cold shrink screened separable connectors.  Cold shrink terminations also enable the installation of underground cables in environments where it is difficult to obtain hot work permits or where hot work is difficult or impossible.

‘Ensto’s products are of high quality, and their dimensions make them easy to install. In addition, the company’s excellent customer service makes co-operation smooth and easy,’ says Holm.

Ensto PRO training on underground cable terminations

Ensto organised a training session on underground cable terminations at the West Metro site in Espoo on 18 September. Ensto Finland’s sales manager Marko Kylliäinen trained electricians from Verkkoviikarit Oy, a subcontractor on the project.  The training session took place in the metro tunnel at Kivenlahti metro station and focused on creating underground cable terminations using Ensto products. The training aimed to ensure the correct installation of the cable accessories in order to guarantee reliable delivery and operation of the metro’s distribution network.

Jussi Tarkiainen, CEO of Verkkoviikarit Oy, was highly satisfied with the training. The training was required by the West Metro, and it provided the necessary skills to create the terminations. The electricians had received training on installing joints one month earlier. ‘The training provided an opportunity to learn about the latest product information in our field, and to experiment and try them out in practice. It also allowed those with limited experience in such work to gain more. Our staff were also excited to learn about Ensto’s certification scheme for electricians’, said Tarkiainen.