5 Key Practices for Effective Preventive Maintenance in Run-of-River Hydro Plants

Build a Living PM Schedule — Not a Static Document

Most plants have a preventive maintenance schedule. Few have one that adapts. The key difference between a schedule that works and one that sits in a drawer is review cadence.

At minimum, review your PM schedule quarterly. Each review should incorporate:

• Actual failure data from the past quarter — which components failed, and when?
• Manufacturer bulletins or updated service intervals
• Seasonal variations in river flow that affect equipment stress levels
• Technician feedback from the field

We moved from annual to quarterly schedule reviews at Telekosang and saw a significant reduction in reactive maintenance calls within the first two quarters.

Prioritise Lubrication as a System, Not a Task

Lubrication failures are responsible for an estimated 40–50% of rotating equipment failures in hydro plants. Yet lubrication is often treated as a simple checklist item — "grease the bearings, tick the box."

A lubrication system approach means:

• Right lubricant selection: Match viscosity and type to operating temperature, load, and speed for each specific bearing
• Right quantity: Over-greasing is as damaging as under-greasing — use calculated volumes, not guesswork
• Right interval: Based on actual operating hours, not just calendar days
• Oil analysis: Quarterly oil sampling for turbine bearings to detect contamination and degradation early
• Storage and handling: Clean, labelled lubricant storage to prevent cross-contamination

Implement Baseline Vibration Monitoring

You don't need expensive predictive maintenance software to benefit from vibration monitoring. A portable vibration meter and a disciplined baseline programme will detect developing faults months before they become failures.

The process is straightforward:

1. Establish baselines on all rotating equipment when it is newly commissioned or after major overhaul
2. Measure at consistent load conditions — same operating point every time
3. Record at fixed measurement points marked on each machine
4. Plot trends monthly — it's the trend, not the absolute value, that reveals problems
5. Set alert thresholds at 150% of baseline; action thresholds at 200%

Control Water Quality at the Intake

Run-of-river plants are exposed to whatever the river carries — sediment, debris, biological matter, and dissolved minerals. Protecting your hydraulic and mechanical systems starts at the intake structure.

Key water quality practices include:

• Trash rack inspection and cleaning: Daily visual check; automated differential pressure monitoring where possible
• Sediment flushing: Structured flushing protocol during high-flow periods to prevent sediment accumulation in the settling basin
• Turbine wear tracking: Dimensional checks on runner wear rings during every major outage — sediment abrasion is a leading cause of efficiency loss
• Water sampling: Monthly pH and turbidity monitoring to detect changes that may indicate catchment events upstream

Close the Loop on Every Work Order

Maintenance documentation is where most small hydro teams lose the most value. Work orders are raised, work is completed, but findings are not recorded — and so the institutional knowledge walks out the door with every technician who eventually moves on.

Close the loop means every completed work order must include:

• Actual findings (not just "completed as per WO")
• Parts used and quantities
• Time taken vs. estimated
• Any deviations from the planned procedure
• Technician observations and recommendations

This data becomes the foundation of your next PM schedule review, your spare parts planning, and your training materials. Without it, you are operating blind.