Remote Power Station Recovery

This remote power station supplies a major gold mining operation. A system disturbance caused stator earth faults on four of the eight operating units. We were engaged to help understand the failure, specify repairs, audit and expedite work across multiple sites, and return the station to service. Repairs were performed in four facilities on Australia’s east coast, and the station was back at full production within six weeks.

Event Timeline

• Disturbance and trip: system event; protection operated; four units reported stator earth faults.
• Week 1: mobilisation and evidence capture; protection/sequence-of-events review; initial RCA.
• Weeks 1–2: repair specifications issued; vendor qualification and awards; logistics confirmed.
• Weeks 2–5: repair work across four facilities with audits and witness testing.
• Week 6: commissioning, staged loading, handover; site returned to full output.

Recommended Reviews (stator-ground focus)

• Ground-fault protection coverage and settings reviewed; logic and alarm paths checked against service philosophy.
• Post-event relay testing completed where applicable (functional/secondary-injection).
• Trip/alarm coordination verified with station protection and plant interlocks.

Activities & Deliverables

• Root Cause Analysis: relay/SOE correlation, failure-mode mapping, and fleet risk screen; evidence pack issued.
• Repair specifications: scope, acceptance criteria, and test plans per unit.
• Vendor qualification: capability, HSE, and QA checks; audit close-outs tracked.
• Workshop audits: materials traceability, process control, and in-process inspection.
• Tender evaluations: technical/commercial assessment and award rationale.
• Expediting: critical-path tracking and inter-facility hand-offs.
• Witness testing: as specified in the repair plans; signed reports retained.
• Commissioning: protection checks, cold/hot runs, staged loading; as-built dossier and handover.

Industry Standard Tests

• Insulation resistance (IR) and polarization index (PI)
• Winding resistance balance
• Surge and hi-pot per specification
• Partial discharge check (where applicable)
• Thermography
• Run-out and alignment checks
• Vibration baseline (cold and hot)

Post-repair Monitoring Options

• GuardII+ — continuous partial discharge monitoring for generators with Stator Slot Couplers (SSC) or 80 pF Epoxy Mica Capacitors (EMC); optional end-winding vibration and rotor-flux modules on synchronous machines.
• PDA-IV / TGA-B — portable PD testing using existing EMC/SSC sensors, with analysis in PDView to compare post-repair baselines with future tests.
• FluxTrac — rotor magnetic-flux monitoring for synchronous units to detect shorted turns during operation.

Outcome

Repairs were executed across four facilities and the station returned to full production within six weeks. The program delivered a verified scope, auditable QA records, and a monitoring approach to lower the likelihood of repeat stator-earth-fault events.