Thordon Bearings has completed bearing and filtration system upgrades to the Swift Rapids hydro power station, the oldest and largest of Orillia Power Generation Corporations’ generating stations, located on the Trent-Severn Waterway, about 32km (20mi) north of Orillia, Ontario, Canada.
Two of the plant’s three 2.6MW horizontal Kaplan-type turbines are fitted with Thordon’s SXL water lubricated guide bearings and all three units are now using the company’s unique water filtration system, which supplies clean water to the turbines’ shaft seals and bearings.Greg Auger, Thordon’s Hydro Business Unit Manager, explained that while two of the Swift Rapids turbines had converted to Thordon’s SXL bearings some years ago, the poor quality of the water supply was impacting the expected longevity of the elastomeric bearings.
“Abrasive waters, particularly from significant zebra mussel growth, were resulting in excessive bearing wear, with Orillia Power having to replace the bearings more frequently than is typical of these bearings. The existing filtration system was quite old, with the operator experiencing frequent breakdowns and expensive maintenance. It was also a single central system, supplying all three turbines, so there was no redundancy in case of breakdown. All three turbines were susceptible to outage in case of a filtration system problem, which could lead to significant loss of generation production.”
When Thordon supplied the most recent replacement bearing and carried out a site inspection in early 2019, the company recommended the installation of its Water Quality Package (WQP) for each shaft line, allowing each turbine to have its own dedicated filtration unit.
“Clean and abrasive free water is critical to maintaining the operational status of the turbines, providing cooling and lubrication for bearings and shaft seals. Providing a consistent source of filtered water provides the optimal conditions for extremely long bearing life,” said Auger.
Commenting on the installation, Carl Sykes, Thordon’s Global Service and Support Manager, said: “There were some initial challenges. When we started removing the old pipework, we found it heavily corroded and there was a high concentration of zebra mussels which was severely impacting the performance and flow of the turbine’s cooling system.”
Based on the plant’s specifications Thordon replaced all of the water intake, cooling and lubrication pipework with copper piping, which the zebra mussels have difficulty settling on. The water filtration system incorporates a cyclonic separator to remove large and abrasive debris larger than 100 micron, and includes an automated purging valve on the drain line that flushes any accumulated debris through to a central drain.
As part of the piping installation and overall system installation work, Thordon also installed additional flow and pressure instrumentation to allow the customer to more accurately monitor and adjust system flow rates to individual devices. An HMI (Human-Machine Interface) system was also fitted on each filtration unit, with feedback to the central plant SCADA system, to allow the plant operator to better control critical operating parameters by way of a real-time display unit.
Troy Mannell, Manager of Generation Projects, Orillia Power Generation Corporation, said: “Orillia Power is looking to lessen the manual interventions across its hydro power plants over the next few years and we consider upgrading to the Thordon filtration system as a way of reducing the maintenance intervention requirement. The reliability of Thordon turbine guide bearings with their advanced water filtration, and separate systems per turbine, can help us achieve greater levels of remote operation, while strengthening plant availability and operability.”
The Orillia project marks an important milestone for the Thordon’s Hydro & Clean Power division.
“We not only supplied the WQPs but we also provided all of the connection piping and installation services. Normally we would only supply the equipment and have other third party contractors installing it at the site, but we felt that our direct involvement in this project would be the most effective way to ensure the best outcome for the customer. We intend to continue offering this comprehensive turn-key service to other customers as part of wider strategy to expand and diversify our Hydro business,” said Auger.
