Forrest Kerr Hydroelectric Facility in Canada recently installed Rotork IQ multi-turn electric actuators for improved torque control.
The Forrest Kerr Facility consists of a diversion weir, intake structure, de-sanding facility, power tunnel, underground powerhouse, tailrace tunnel and an associated electrical substation and transmission works. Unlike regular hydroelectric plants that impound water within a dam, Forrest Kerr redirects a part of the river water to an intake structure near to the meeting point of Forrest Kerr Creek and the Iskut River. This process leaves behind a smaller environmental footprint and minimises the impact on terrestrial and aquatic ecosystems.
The IQ actuators replaced electric actuators from another manufacturer at the intake structure and divert 250m³ of water per second. The original actuators, mounted on conventional knife-gate valves, were unable to meet the increased operating torque requirement when excessive sand and grit build-up was experienced around the valves.
Rotork representative Summit Valve and Controls Inc. were invited to present a solution and were ultimately awarded the contract for valve and actuator replacement. The solution consists of Rotork IQ40 actuators mounted on custom-designed knife gate valves with 35 ft (10 m) extended bonnets. The replacement IQs are oversized by design, allowing Forrest Kerr to temporarily increase torque output via Bluetooth® remote when the application conditions are more demanding.
Furthermore, the IQ onboard datalogger offers an insight to the application, monitoring and comparing valve torque requirements relative to the initial ‘clean’ reference stroke and identifying when excessive sand is building up within the basin.
Forrest Kerr is a 195 MW hydroelectric facility owned and operated by Canadian energy company AltaGas Ltd. It is capable of generating enough electricity to power approximately 70,000 homes in British Columbia and will offset more than 450,000 tonnes of greenhouse gases annually.