McNary Northshore Fishway Hydro Project History & Lessons Learned May 6, 2017
21 th Annual TECHNICAL SEMINAR Machines, Maintenance, and Management: Keeping Hydro Facilities Up and Running History & Lessons Learned McNary Northshore Fishway Hydro Project McNary project history McNary re-powering project aka Runner install (part 1) Powerhouse crane failure & repair Rewind Project Runner install (part 2) Commissioning Lessons learned
McNary Lock and Dam
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Brief Project History On September 30, 1991, the Federal Energy Regulatory Commission (FERC) issued a 50-year license to North Wasco County Peoples Utility District (NWCPUD) to construct, operate and maintain a hydroelectric project at the McNary Dam. Originally, BPA entered into a power purchase agreement with NWCPUD in 1993. BPA withdrew from the agreement in 1994. Klickitat PUD then joined with NWCPUD to develop the McNary Project. The PUD s entered into an Ownership Agreement in August of 1995 The McNary North shore hydroelectric project was completed and started production on October 17th 1997. The total cost of the project was $29 million.
7 Project Design The project uses attraction water from the north shore fish ladder on the McNary Dam for power generation. Attraction water flow is diverted through penstocks, runs through the turbine and is then routed back to the entrance of the fish ladder to attract migrating fish and lamprey. The intake structure at McNary is located at the bottom of the dam and draws water from about 80 ft below the surface of the dam forebay. The generator at McNary produces approximately 10 MW of power, which is split equally between NWPCUD and KPUD. Over a year, this amounts to approximately 80,000 MWh of energy enough power to provide electricity to about 8,000 homes
Construction Photos
Kurt 9 Conger, NWCPUD
McNary Fishway Hydro Project Unit Cross Section
McNary Re-powering Project Runner Install - Part 1 Review repair history of turbine blade cracks Review welding procedures from past blade repairs. Evaluate failure risk and cost associated with a blade failure Recommend remedial protection measures, e.g. vibration monitoring, startup/shutdown timing, other, that may mitigate damage if a blade failure occurs. Make recommendations for repair or replacement of turbine runner or other in-water equipment.
Project Information 10 MW vertical unit commissioned in 1997 Orenco supplied Hangzhou turbine & generator, manufactured in China History of propeller runner blade cracking Runner casting quality poor with dimensional problems Initial McMillen Jacobs site visit on June 17, 2014 Annual outages with weld repairs
Early cracks near anti-cavitation fin
Cracks needing repair every 6 months
Cracks getting worse after each weld repair
Crack NDE
Recommendations Contract for additional engineering, including developing contract documents Perform generator detailed inspection early 2015 Bid and award new runner contract Bid and award runner install site work contract Action: Owners direct McMillen to develop runner procurement bid documents and runner installation bid documents.
Runner Procurement Bid documents prepared and issued to bidders Bids evaluated and recommendation for award February 2015 Weir American Hydro awarded contract effective March 31, 2015 Runner to be delivered within 311 days
New Runner
Old Runner
Runner Installation Contract Bid documents prepared and issued to bidders Bids evaluated and recommendation for award August 2015 HCMS awarded contract effective September 9, 2015 Runner to be installed by February 5, 2016 Outage begins October 2015
November 18, 2015 - Crane Failure During the last lift of major equipment from the turbine pit, a defective weld in the powerhouse crane failed. The old runner, shaft, bearings, brackets and head-covers dropped 18. Parts of the crane fell into the powerhouse damaging the stator and concrete. Nobody was injured!
Powerhouse Crane
Crane Failure Damage The crane failure damaged several major components of the project: Generator stator windings and core Turbine bearing bracket that supports the runner and shaft Lower guide bearing support bracket And the crane itself was no longer serviceable for the runner installation work
Other Component Defects Stator winding defects Loose wedges and missing side/depth packing Caused excessive wear, winding damage and reduced life expectancy Lack of strand transpositions or internal transpositions resulting in higher losses Tin/lead solder results in higher losses and increased outage risk Other (PD evidence, inadequate end winding clearances) Wicket gates, bearing surface degradation, runout measurements too high Multiple inner and outer head cover defective welds Upper and lower bearing bracket defective welds Possible defective rotor welds investigated need rewelding
Project Timeline Late 2015: HCMS Stabilized the Project Early 2016: Disassembly of Plant Components Feb-Aug 2016: Off-site Component Repairs May-June 2016: Crane Repair and Installation April 2016: Boards Authorized Stator Rewind May-July 2016: Stator Rewind June-October 2016: Reassembly of Plant Nov 2016 Feb 2017: Commissioning
Generator Rewind Based on inspections during repair of damage to stator core laminations a rewind was recommended Developed rewind bid documents and issued bid documents Evaluated bids and awarded a contract for stripping coils and installing new to National Electric Coil (NEC) After coils were manufactured HCMS took short break while installed new windings
Runner Install Part 2 While rewind was underway 300 ton mobile crane used to service work Meanwhile powerhouse crane components are repaired/replaced HCMS weld repairs rotor spider following EME fracture mechanics analysis HCMS begins reassembly of unit in July 2016 following rewind Other work included: headcover line bored for wicket gate bushings, discharge ring machined, wicket gate stems repaired, bracket weld repairs, etc. Unit alignment complete in November 2016 Unit water up attempted mid-november 2016, but leakage from wicket gate cartridges causes delay Corp of Engineers ladder outage (December 2016 through January 2017) delays commissioning to February 2017. Commissioning begins February 7 and is complete February 12, 2017
Commissioning
Turbine Output (MW) Turbine Power vs. Servo % 12.0 11.0 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 40 45 50 55 60 65 70 75 80 85 90 95 100 Servo %
Commissioning Conclusions Runner met guaranteed output Load rejection unit speed rise and pressure rise acceptable Generator temperature rise acceptable Bearing temperatures acceptable Vibration levels below maximum allowable
Lessons learned Purchasing Chinese equipment is risky extreme vetting is needed Weld repair of CA6NM castings very difficult Crane load testing isn t the final word Need a good team to recover from an extreme situation Be prepared to respond to changed conditions based on disassembly inspections Watch out for bad paint system specifications
Acknowledgements NWCPUD and KPUD staff HCMS American Hydro National Electric Coil Congratulations to Bob Guidinger on his retirement!
Questions?