Recently, I had the opportunity to participate in a Factory Acceptance Test (FAT) for servomotors of jet deflectorls. A double Pelton turbine with a bruto head of 550 meters and 2 kilometers long penstock behind - these are typical generating Units in HPP Perucica. The huge nominal head and long penstock are ideal conditions for the water hammer effect. 😊 To avoid this destructive physical phenomenon, it is crucial to establish laws for closing the nozzles and main inlet valves, allowing enough time for pressure oscillations in the penstock to settle. On one hand, we have water hammer, which requires slow needle valve closure, and on the other hand, the need for quick response to separate the turbine from water supply in case of load rejection to prevent Unit overspeed. How? Jet Deflector, robust, reliable, mechanism that, within 1.5 seconds, cuts off the water jet, separating it from the runner blades, giving the nozzles sufficient time to gently close the water inlet without the risk of water hamer effect is the most important safety part of a Pelton turbinehe.
The comprehensive FAT included several critical tests:
Pressure Tests: We rigorously tested both the oil side and water side pressure systems.
Function Tests: These covered various aspects, including the cylinder function according to the test plan, cushioning behavior, and transducer functionality.
Measurement Tests: We meticulously measured stroke, flange dimensions, fork head alignment, chrome layer quality, and paint finish.
Our dedicated team, including Marko Janković , Gojko Blagojevic, and myself, ensured that the control panel met all design specifications. It was a rewarding experience to verify the system’s performance before deployment.
Assistant Professor at Private Engineering College
3moVery helpful, dealt with much details