In recent years, Maintpartner has renovated several of UPM Energy's hydropower floodgates at river Kymijoki, Finland. Maintpartner typically carries out the entire project including construction, engineering, dismantling, coating and installation works. The fourth renovation project will be completed this summer at Kaltimo hydropower plant in eastern Finland.
During the basic renovation, the motor drive, seals and other wear parts of the floodgate are renewed. The gate itself is sandblasted and re-coated. After the work is completed, the gate is as good as new - and operates better and safer with modern and environmentally-friendly technology.
The upgrade includes heating and venting systems in the gates to protect the gate surface structures from ice formation. New oil-free bearing solutions for raising and lowering side guides minimize the risk of environmental damage. Additional instrumentation accurately identifies the position of the gate and the need for adjustment that is controlled remotely.
The environment and safety are carefully taken into account in the renovation. The site is fully covered to prevent the blasting sand and paint waste ending up in the water. The gate is carefully supported in an upright position, and on the downstream side there are guardrails to prevent workers from falling into a steep rapid. Survival crafts and life buoys are always available at site.
“Continuous maintenance and upgrading of hydropower plants are important for maintaining plants so that they are efficient and environmentally safe. The amount of oil in the equipment has been significantly reduced, and the well-maintained plant works as planned also in exceptional situations – for example, during floods,” says Hydropower Manager Pekka Pollari from UPM Energy.
“We have personnel specialised in dam projects, and their expertise is crucial. Our project manager Pekka Nokelainen and our skilled technicians work in close cooperation with UPM Energy,” says Team Manager Teemu Torvikoski from Maintpartner’s Kouvola office.
The Voikkaa hydropower plant was originally completed in 1923 as the power plant of the paper mill of the then Kymmene Oy. Other tenants now occupy the former paper mill premises, and the electricity of the Voikkaa power plant is sold on the market. With a production capacity of 1,500 MW, UPM Energy is Finland's second largest producer of electricity who generates electricity in hydropower, nuclear power and CHP plants. The company's goal is to grow as a producer of CO2-free electricity and as an expert in industrial energy efficiency.
How the work progressed on the dam of the Voikkaa hydropower plant last summer:
First, the divers built a temporary wooden dam between the floodgate and the reservoir. The wood material was transported to the site on a ferry.
When the gate had been raised up and supported, the old seals were removed. The side guides were renewed, the rack rails repaired and the old motor drives removed. The new motor drives and their transmissions were installed on the newly-built foundations.
The floodgate technology was renewed including the heating and venting systems. The gate was sandblasted, the damaged parts repaired, spackled and painted.
Finally, the leak tightness was secured by adjusting the new seals, and the renewed gate was put into service.
Photos below: The downstream side of the floodgate before the renovation. The gate is supported up and the seals have been removed from the bottom. Behind it is shown the temporary wooden gate.
The renewed floodgate in lowered position; in the middle is the service door for accessing the gate for e.g. electrical and automation maintenance work.
Teemu Torvikoski, team leader, Maintpartner Voikkaa/Kouvola
Kari Aalto, President, Project, Installation & Engineering Services