Yards Creek Rotor Poles

J.J. Geuther

Asia Pacific PartnershipUnited States of AmericaPower Generation Task ForceAugust 13 – 17, 2007

Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Project Details

Replacement of all amortisseur bars—poles must be removed and clamping heads removed.

Refurbishment of pole windings—asbestos turn insulation removal; new groundwall insulation.

Modification of pole clamping heads for reduction of stresses at step in amortisseur bars.

New pole keys.

Specialized tooling for pole rework.

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Project Details

All 30 poles were removed and refurbished.

National Electric Coil (NEC) handled the insulation removal and pole refurbishment.

Millwrights under FE supervision removed, prepared for transport and re-installed the poles

Project was completed in 49 days workingtwo hour shifts, 7 days/week.

All poles had to be removed via thegantry crane—up through thepowerhouse roof.

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Project Details

Additional challenges included key removal and rigging of poles.

Two poles were worked on simultaneously from opposite sides of the rotor. Only one could be removed at a time due to crane constraints.

The remote control of the gantry crane wascritical for the close tolerance work.

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Project Details

Early delivery of poles to the repair shop was critical.

It was decided to perform work without removal of the rotor to expedite pole removal.

Other work items were identified.

Microsoft Project was used for project planning.

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Concurrent Work Unit No. 1:

– Inspection of M-G and P-T– Governor Unloader Modification

Unit No. 3:– Inspection of M-G and P-T– Governor Oil Pump Unloader Modification

Unit No. 2: – Inspection of P-T– Replacement of Wicket Gate Stem Packing– Thrust Bearing Oil Cooler Replacement.– 230kv GCB Control Wiring Replacement– Lower Guide Bearing Oil Cooler Inspection– Equalizing Line Inspection– Installation of Air Gap Instrumentation– Stator Cleaning and Corona Repair

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Concurrent Work

Common Plant Items:• Dewatered Inspection of Penstock and Tunnel• Upper Reservoir Intake Inspection• Replacement of Spherical Valve Bypass Line Guard Valves• Replacement of 6” Nozzles on Penstock Upstream of

Spherical Valve• Modification of Tailrace Trashracks• Penstock Rocker Repair• Penstock Expansion Joint Repairs• 230kv Phase Reversal Switch Maintenance

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Removal of Rotor Poles

Removal of Rotor Pole

Rotor in Place

Outdoor Gantry Crane

Close Tolerances

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Pole Removal

Rotor Rim With Poles Removed

Damage Pole Iron—2 Broken Amortisseur Bars

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Damage Pole Iron

Damaged Pole #20 (2002)

2 Broken Amortisseur Bars

Damper Bars Unsupported in Clamping Heads

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Cracked Damper Bar

Removal of Rotor Pole

Rotor in Place

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Winding at Removal

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Amortisseur Bars

Amortisseur Bars Following Removal

Crack in High Stress Area of Amortisseur Bar

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

Stator Corona System

Corona Paint Restored

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

What Can Be Done Better

Amortisseur series connection hardware difficult to install.

Handling and laydown of rotor poles.

Access through powerhouse roof.

Safety and access to stator improved by new decking.

Early delivery of replacement keys, amortisseur bars, shorting rings, etc.

Incentive for Contractor performance on critical path.

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Asia Pacific Partnership • Aug 13 - 17, 2007FirstEnergy Corp. & Duke Energy Corporation

What Can Be Done Better

Item #28 Hardware Modification

Expedite Installation

Improved Quality Control

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