News article


Isohaara hydropower plant to begin modernisation of electrical automation

The automation modernisation of generators 3 and 4 will begin at the Isohaara hydropower plant of Pohjolan Voima in Kemijoki. The work will be completed in April 2017. The modernisation will ensure the production and control capacity of the power plant in the generation of renewable domestic load-following power.

The electrical automation modernisation project involves the automation systems of generators 3 and 4 at Vallitunsaari in Isohaara, which date back to the early 1990s. The turbines and generators will also be serviced during the project.  The automation modernisation will ensure the production capacity of the Isohaara power plant in the generation of renewable domestic load-following power. The modernised automation systems will also streamline the monitoring and troubleshooting of the equipment.

“The modernised automation enables us to utilise the power plant better for just-in-time production of load-following power that balances the consumption and production of electricity,” says Juha Kähkölä, Maintenance Manager at Pohjolan Voima’s PVO-Vesivoima hydropower plant .

“The new technology provides more accurate information on how the condition of the instrumentation is developing, and performing change work and servicing is possible via remote connection, making maintenance work easier. In addition, compared to the earlier situation, the new relay technology saves space due to the need for considerably fewer electrical cabinets. Cost savings are also generated in cabling through the more advanced data transmission and bus technology.” 

The work on generator 4 at Vallitunsaari in Isohaara will begin on Wednesday 7 December 2016, and according to a preliminary schedule, it will be completed towards the end of February. Thereafter, the automation will be modernised in generator 3. The automation modernisation project will be completed in mid-February 2017.

Finnish power plant competence

The electrical automation modernisation project will employ around ten people. ABB from Vaasa was selected as the supplier.  The installation will be carried out by Ases Installaatiot from Kemi. The servicing of the turbine hydraulics, to be carried out in connection with the electrical automation modernisation, will be performed by Tormets Oy from Tornio, and Voith Hydro Ab will be in charge of inspecting the turbines and generators. The project will also involve professionals from Caverion Suomi Oy.

The investment is part of the hydropower plant overhaul programme of Pohjolan Voima. Hydropower plants are overhauled around every twenty years. Both generators at the Melo hydropower plant on Kokemäenjoki River were overhauled in 2014–2015. A major overhaul project, involving four power plants, was completed in Iijoki in 2013. An overhaul of Raasakka power plant is planned for 2018–2019.

For more information, please contact: Maintenance Manager Juha Kähkölä, PVO-Vesivoima Oy, tel. +358 10 478 622

PVO-Vesivoima Oy is a power production company that is part of the Pohjolan Voima Group. The company operates and maintains hydropower plants on the Iijoki, Kemijoki and Kokemäenjoki rivers. The total annual energy production output of the company is approximately 1.7 TWh. 

Technical specifications of Isohaara power plant

- Generators 1 and 2 completed in 1949
- Power plant generators 3 and 4 in Vallitunsaari completed in 1993
- Total number of generator sets at the Isohaara power plant: 4
- Combined capacity of the power plant: 113 MW
- Capacity of generators 3 and 4: 62 MW
- Total utilisable flow: 1,100 m³/s, of which generators 3 and 4 account for 600 m³/s
- Height of fall: 12.2 m