Large investment in Olkiluoto hub

Olkiluoto substation, which is one of the most important main grid hubs, will be renewed using a solution that is unique in Finland. Once Olkiluoto 3 is completed, the substation will be linked to three nuclear power plants that produce one-third of the electricity consumed in Finland. The 10 million-euro project is one of Fingrid’s […]

Olkiluoto substation, which is one of the most important main grid hubs, will be renewed using a solution that is unique in Finland. Once Olkiluoto 3 is completed, the substation will be linked to three nuclear power plants that produce one-third of the electricity consumed in Finland. The 10 million-euro project is one of Fingrid’s largest investments.

The entity located at this key main grid hub will consist of three switchyards and control room buildings. The existing and ageing 
Olkiluoto A switchyard built in the late 1970s will be dismantled and replaced by a new two-part 400 kV switchyard to meet the needs of the Olkiluoto 1 and 2 nuclear power plants.

Duplex circuit breaker system guarantees reliability

In addition to the Olkiluoto B switchyard built to connect the Olkiluoto 3 plant, the entity will be complemented by C and D switchyards and control room buildings. The new duplex circuit breaker system will improve system security for the substation and allow for a variety of connections in different disturbance and maintenance outage situations.

“The existing dual-rail transfer bar structure will no longer meet system security requirements in the future. A new duplex circuit breaker system structure will make it possible to more reliably separate the Olkiluoto power plants from each other. The switchyard solution also enables nearly unlimited connection options when dealing with disturbance and outage situations,” says Fingrid’s Project Manager Hannu Heikkinen, who is responsible for the project.

“Olkiluoto’s 400 kV substation will be the only one of its kind in Finland. The circuit breaker bays built between the switchyards allow different types of connections, which means that electricity can be reliably transmitted to other parts of Finland even during disturbances,” says Heikkinen.

Olkiluoto’s renewed substation will be commissioned in 2019.