Custom-built compact secondary substation (CSS) secures electricity supply on an island
The island of Stora Fjäderägg outside Umeå is famous for nature lovers and birdwatchers. When Umeå Energi future-proofs the island’s power supply, Holtab will be involved in delivering a custom-built compact secondary substation (CSS) with a reserve power unit.
The barren island of Stora Fjäderägg in the Gulf of Bothnia outside Umeå is historical land. In medieval times, fishing and seal-hunting teams met here, as far out as possible in Umeå’s archipelago. Today, the island is a nature reserve that attracts crowds of birdwatchers and outdoor enthusiasts every summer.
In the middle of the island is a decommissioned lighthouse and around it are a handful of properties, which today serve as a hostel. There are no permanent residents on the island, nor any drivable roads.
"Holtab always delivers quality goods"
The island has had electricity for many years with a sea cable running to the large Holmön island to the south. The substation on the island has been integrated into the lighthouse. More than 10 years ago, the Swedish Maritime Administration decided to cease operation of the lighthouse and it is now owned by a private individual.
"At Umeå Energi, we wanted a modern substation that was independent of the lighthouse, as it is currently privately owned. When we invested in a new station, we also decided to replace the sea cable to Holmön and the land cable at Stora Fjäderägg," says Per Lindberg, Electrical Safety Manager at Umeå Energi.
Holtab was the company with the best expertise to build the new station.
"I’ve been at Umeå Energi for 35 years and have always worked with Holtab’s products. They have always delivered quality products, both when it comes to their standard stations and when it comes to special orders like this," says Per Lindberg.
Transported on a timber trailer
Once on the island, the station was lifted onto a timber trailer — a trailer normally used for transporting timber in the forest — which, with its large tyres, can haul the station, weighing several tonnes, across the pebble-strewn fields.
Then the station, painted red like the surrounding houses and sheds, was placed in a spot where it blends into its surroundings.
"If there is a power outage, it takes too long for our technicians to reach the site. That’s why we had to have a new station with backup power units. This is our legal obligation. It’s a costly project and there’s a lot of work to get the station in place, but we’re very pleased with the result," says Per Lindberg at Umeå Energi.
The Challenge
Umeå Energi needed to secure the power supply on the island of Stora Fjäderägg in Bottenviken (the Bothnian Bay). The island is situated far away, and in the event of a power outage, it can take time for technicians to get there, for example due to storms or poor ice conditions. Therefore, a modern network station with a backup power unit was needed.
The station had to comply with the industry standard EBR KJ59 and be lifted with equipment mounted, both by overhead lift and from below with, for example, pallet forks. It would have a three-day operating time at 25% load and it would be possible to communicate with the station from an operations centre. The backup generator is required to automatically start and take load in the event of an outage.
The solution
Holtab developed a specially adapted substation that met the above requirements. It was built on site in Tingsryd and then transported to Umeå. There it was shipped to the island of Stora Fjäderägg. On the island, it was transported by timber trailer over pebble-strewn fields.
Details:
• Holtab developed the TSK 315–3, 12 kV substation with room for a backup generator.
• The low-voltage switchgear with mains and generator circuit breakers controlled by the backup power unit’s automatic control system is specially designed by Holtab.
• The 40 kVA diesel generator with associated control system has been supplied by Eitech.
• Remote control equipment with Rakel communication has been supplied by Techinova.
Result
A new substation has been installed, together with a new land and sea cable. The island of Stora Fjäderägg in Bottenviken (the Bothnian Bay) has future-proofed its electricity supply and Umeå Energi can supply electricity in accordance with the Electricity Act.
Contact
Andreas Öberg
Energy Distribution, North Sweden, Electricity Area 1 & 2+46 73 145 12 19andreas.oberg@holtab.se
