Procedure: Routine Wind Turbine Maintenance

Purpose. This procedure describes how technicians plan, isolate, perform and record a scheduled maintenance visit to a large scale wind turbine at Ridgeback.

1.Scope

This procedure applies to six monthly and annual scheduled maintenance of the wind turbines at Ridgeback, including tower, nacelle, hub and control system tasks. It must be read with the Permit to Work and Isolation Policy and the work at height requirements.

2.Step 1: Plan the visit

The technician must check the weather forecast and wind speed against the working limits, must confirm the maintenance task list from the work order, must load the parts and consumables and must notify the control room of the turbine to be taken out of service and the expected duration.

3.Step 2: Isolate

The turbine must be stopped and the rotor locked before any work in the hub or on the drive train. The electrical isolation must be applied at the turbine switchgear, locked and proven dead. The control room must record the turbine as out of service and the register must show the permit.

• Stop the turbine and apply the rotor lock
• Isolate, lock and prove dead the turbine electrical supply
• Confirm the yaw and pitch systems are isolated where required
• Record the permit and isolation in the register

4.Step 3: Perform the tasks

The technician must complete the task list in order, recording torque values, oil levels and sample results, brake pad wear, sensor checks and any defect found. Work at height must use the climb assist and fall arrest systems. Two technicians must be present for any work in the nacelle.

5.Step 4: Return to service

The technician must remove tools and consumables, remove the rotor lock, restore the electrical isolation, run the turbine control system self test and request the control room to release the turbine to automatic operation. The technician must watch the first start from the base.

6.Step 5: Record

The work order must be closed with the task results and any new defects raised as separate work orders. Climatic conditions during the visit must be entered in the Operations Log.