“The basic prerequisite for choosing a new substation location is that the transformer can be transported there,” summarises Fingrid’s Senior Expert, Construction, Mikael Wiren.
Transformers are brought to Finland on ships. They are transferred from the port by train as close as possible to the destination. From the train track, the transformer is loaded onto a lorry for the last part of its journey.
The transformers are purchased with delivery to the site, but Fingrid ensures that there is a path to the substation on the ground.
“It can take 15 minutes to find a route or maybe as long as 5 years. Much depends on whether the infrastructure requires intervention, such as building a new bridge,” Wiren says.
It is very demanding for the route: a transformer ready for transportation weighs 300 tonnes, is 6.5 metres high and 3.5 metres wide. There are often bridges that pose challenges when choosing a route if the transformer cannot fit under the bridge or if the bridge cannot withstand the weight of the transformer.
Road widths and elevation differences should also be taken into account, as the route must not have very steep uphill or downhill slopes; the transformer needs to get up the hills and the brakes must be able to withstand going downhill. The structure of the road may also be inadequate to withstand heavy transport.
Bridges are bottlenecks
Once the route has been planned, Fingrid obtain an advance transport permit from the Centre for Economic Development, Transport and the Environment. The carrier, in turn, obtains the actual transport permit closer to the time.
For a preliminary transport permit, the Finnish Transport Infrastructure Agency issues an opinion on the durability of the bridges, the Centre for Economic Development, Transport and the Environment issues an opinion on the load-bearing capacity of the state’s roads, and cities issue opinions on their infrastructure.
If the permit is declined, another route must be found. If the decision is conditional, work must begin to address the terms and conditions.
“It is possible to negotiate road repairs, culvert and asphalt replacements, support structures or other issues with different parties. For bridges, there is no room for negotiation, because the bridge can either withstand a load or not based on calculations,” Wiren says.
Routes with a long life cycle
A substation has a service life of 80 years, and the transport route used by the transformer must have the same life cycle. A new transformer may be needed to replace a broken one, or power demands may increase, such that additional transformers are needed in a substation.
“There are a lot of cases where the original routes are out of use. Inspection for transport may show deterioration of a road or bridge so that it can no longer withstand the weight of the transformer. In the future, more preparations will be needed for these kinds of situations as the traffic infrastructure ages.”
It is important to be vigilant about life cycles. If there is an opportunity to improve a route in connection with the construction of infrastructure, it is good for Fingrid’s route planners to be involved.
Watch a video of a transformer travelling from Vuosaari harbour to Hepokorpi, Espoo (In Finnish):
You can watch the video also in here.
