Procedure: Planning a Scheduled Outage

Purpose. This procedure describes how the planning team scopes, schedules, resources, costs and approves a scheduled outage and how the outage is executed and returned to service.

1.Scope

This procedure applies to every planned outage of a gas turbine, the steam turbine, the hydro unit or the wind farm collector system that removes capacity from the market. Minor maintenance within a unit's normal availability is managed through work orders.

2.Step 1: Scope the outage

The planner must compile the scope from the maintenance strategy, the open defects, the condition monitoring results and the regulatory inspections due. Each scope item must be linked to a work order and assessed for its effect on outage duration.

3.Step 2: Schedule

The planner must build the schedule with the critical path, the daily labour and crane requirements and the isolation windows. The outage must be submitted to the market operator through the medium term availability process and confirmed with the transmission network operator.

• Critical path and float for each scope item
• Daily labour, crane and scaffold plan
• Isolation and switching windows
• Market operator availability submission

4.Step 3: Cost and approve

The planner must prepare the cost estimate with labour, contractors, parts and consumables and must compare options where scope can be deferred. The Station Manager approves the outage plan and budget.

5.Step 4: Execute

A daily outage meeting must review progress against the critical path, safety, quality hold points and emerging work. Emerging work must be assessed for its effect on the return to service date before it is approved.

6.Step 5: Return to service

Every work order must be closed, every isolation restored and the commissioning checks completed before the unit is released to the control room for start. The planner must record the actual duration and cost and hold a lessons learned review.