Operations – Poster Presentations
CLEAN CURRENTS 2026
Time: 2:30 PM - 3:30 PM
Day: 9/23/2026
Room Number: CC Central: Learning Center (Wednesday Posters)
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Details about each presentation and the speakers are below:
In this session:
Mitigating Fatigue Risks in Hydro-Turbines through Rotor-Stator Interaction (RSI) Monitoring
Not the Usual Suspect: Identifying Non-Obvious Sources of Shaft Current in Hydro Generators
Mitigating Fatigue Risks in Hydro-Turbines through Rotor-Stator Interaction (RSI) Monitoring
Presented by Ozren Oreskovic, VESKI, a member of Dewesoft
In hydrogenerator turbines, the passing interactions between the turbine runner (rotating blades) and the guide vanes (stationary blades) generate pressure pulsations due to unsteady flow fields and wake effects, a phenomenon known as rotor-stator interaction (RSI). These pressure fluctuations, if severe, can lead to excessive vibrations, noise, and even fatigue failures in the turbine components, which can significantly influence turbine performance, structural integrity, and maintenance schedules.
RSI often induces increased vibrations and pressure fluctuations at specific frequencies, usually related to blade-passing frequencies. Repeated stress and resonant effects on these frequencies can lead to cracks in the runner blades, runner rings, and labyrinth seals, and can affect other machine parts.
Deploying an online condition monitoring system that simultaneously tracks critical parameters is essential for mitigating the impact of severe rotor-stator interaction (RSI) induced dynamics. An effective system integrates multiple diagnostic techniques, including vibration monitoring, strain gauge measurements, and dynamic pressure sensing, to accurately detect and analyze pressure pulsation-induced vibrations.
Not the Usual Suspect: Identifying Non-Obvious Sources of Shaft Current in Hydro Generators
Presented by Aaron Doyle, Iris Power - Qualitrol
Shaft voltage and current anomalies in hydro generators are more common — and more varied in origin — than many operators realize. While uninsulated bearings are the well-known culprit, localized current loops can form along the shaft in ways that are far less obvious and easy to overlook during routine maintenance and outage work.This poster walks through a real-world case from a large hydro generator where a proximity sensor at the upper guide bearing was improperly installed in direct contact with the rotating shaft without insulation. The unintended contact formed a localized current loop, producing 83 amps peak-to-peak of shaft current and causing a shunt resistor to burn — damage that could easily be misdiagnosed or attributed to other causes.
The core message: seemingly minor instrumentation or maintenance decisions — a sensor installed without adequate insulation clearance — can create significant electrical anomalies. Awareness of these less obvious failure pathways is the first line of defense. Visual documentation of the problem is included to help attendees recognize similar conditions in the field..
This session takes place in the Learning Center, which is sponsored by:
