Yards Creek Rotor Poles Asia-Pacific Partnership on Clean Development and Climate Yards Creek Rotor Poles Asia Pacific Partnership United States of America Power Generation Task Force August 13 – 17, 2007 J.J. Geuther

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. Yards Creek Rotor Poles 2

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 working two hour shifts, 7 days/week. All poles had to be removed via the gantry crane—up through the powerhouse roof. Yards Creek Rotor Poles 3

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 was critical for the close tolerance work. Yards Creek Rotor Poles 4

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. Yards Creek Rotor Poles 5

Concurrent Work Unit No. 1: Unit No. 3: Unit No. 2: Inspection of M-G and P-T Governor Unloader Modification Unit No. 3: 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 Yards Creek Rotor Poles 6

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 Yards Creek Rotor Poles 7

Removal of Rotor Poles Removal of Rotor Pole Rotor in Place Outdoor Gantry Crane Close Tolerances Yards Creek Rotor Poles 8

Pole Removal Rotor Rim With Poles Removed Damage Pole Iron—2 Broken Amortisseur Bars Yards Creek Rotor Poles 9

Damage Pole Iron Damaged Pole #20 (2002) 2 Broken Amortisseur Bars Damper Bars Unsupported in Clamping Heads Yards Creek Rotor Poles 10

Cracked Damper Bar Removal of Rotor Pole Rotor in Place 11 Yards Creek Rotor Poles 11

Winding at Removal Yards Creek Rotor Poles 12

Amortisseur Bars Amortisseur Bars Following Removal Crack in High Stress Area of Amortisseur Bar Yards Creek Rotor Poles 13

Stator Corona System Corona Paint Restored Yards Creek Rotor Poles 14

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. Yards Creek Rotor Poles 15

What Can Be Done Better Item #28 Hardware Modification Expedite Installation Improved Quality Control Yards Creek Rotor Poles 16