Nam Peun 1 Hydropower Plant

Project Overview

Nam Peun 1 hydropower site is located on the Nam Peun (river) in Houameuang District of Houaphan Province about 3 km north of Ban Sop Peun village (where the Nam Peun joins the Nam Neun river). is currently experiencing operational issues due to a damaged bearing system. Maintenance teams have been notified to conduct a detailed inspection, replace the faulty components to restore optimal performance.

The Challenge: Thrust Bearing & Thrust Collar fail due to extreme heat



Plant operators reported that both Unit 1 and Unit 2 experienced inoperability due to bearing failure. After a thorough investigation, our team identified three major cause

1.Unit 1 ,2 Oil for Lubrication is not readily available.

2.Unit 1 Thrust Bearing ail due to extreme heat

3.Unit 2 Thrust Bearing & Thrust Collar fail due to extreme heat.

Solution & The Result

Unit-1



1. Replacing the Thrust Bearing

• Objective: Replace the worn-out thrust bearing to ensure the turbine operates smoothly and efficiently, minimizing the risk of downtime.
• Outcome: The thrust bearing was replaced successfully. Performance tests indicate normal operation with no anomalies.

2. Changing Oil for Lubrication Oil System

• Objective: Replace old oil to maintain optimal lubrication, reduce friction, and prevent overheating of moving parts.
• Outcome: The lubrication oil was changed successfully, with improved system performance and no leaks detected.

3. Changing Oil for Oil Pressure Unit

• Objective: Ensure proper oil pressure is maintained to support efficient turbine operation and avoid system failures.
• Outcome: The oil for the pressure unit was changed successfully, ensuring stable and optimal pressure levels.

Unit-2

1. Replacing the Thrust Bearing

• Objective: The thrust bearing was found to have excessive wear, which could lead to operational inefficiencies and potential failures. Timely replacement was necessary to maintain turbine performance.
• Outcome: The new thrust bearing has significantly reduced operational vibrations, leading to improved efficiency and a quieter operation. Regular monitoring has shown optimal performance metrics.

2. Changing Oil for Lubrication Oil System

• Objective: An oil change was imperative for the lubrication oil system to ensure all moving parts function smoothly and to prevent overheating and wear.
• Outcome: The lubrication system now operates with enhanced efficiency, ensuring minimal friction and wear, thereby extending the lifespan of critical components.

3. Changing Oil for Oil Pressure Unit

• Objective: The oil pressure unit required a complete oil change to maintain consistent hydraulic pressure vital for the plants control and safety systems.
• Outcome: The oil pressure unit now sustains stable pressure levels, enhancing the reliability and responsiveness of the hydraulic control systems.

4. Repair Thrust Collar

• Objective: The thrust collar exhibited signs of surface wear, potentially affecting its interaction with the thrust bearing and causing misalignment.
• Outcome: The thrust collar now engages effectively with the thrust bearing, reducing wear and enhancing the overall stability and efficiency of the turbine assembly.

Conclusion

The maintenance interventions on Unit-1 and Unit-2 successfully addressed critical operational components, including thrust bearing replacements, lubrication oil changes, and pressure unit servicing, which collectively enhanced turbine efficiency, stability, and longevity. Performance metrics post-maintenance showed reduced vibrations, improved pressure regulation, and optimized lubrication, confirming the effectiveness of these actions.

However, critical concerns emerged during startup tests for both units. In Unit-1, unintended runner speed escalation to 300 rpm (despite closed valves) highlighted a malfunction in the guide vane system, compromising speed control. Similarly, Unit-2 exhibited analogous issues, with runner speeds reaching 112 rpm and a stuck servo motor in the governor control system, further underscoring systemic instability.

These recurring malfunctions pose risks of component damage, operational inefficiency, and safety hazards. To mitigate these risks, immediate comprehensive overhauls are imperative for both units, focusing on the guide vane mechanisms, control systems, and governor components. Proactive inspections, recalibrations, and component replacements will ensure reliable speed regulation, system stability, and long-term operational integrity. Addressing these issues promptly will safeguard turbine performance, minimize downtime, and uphold safety standards across the facility.