12_13 Jan 21 Fort Randall Site Visit Presentation.pdf

FORT RANDALL DAM

MAJOR UNIT REHAB

SITE VISIT

12 / 13 JAN 2021

SOLICITATION: W9128F21R0005

SITE VISIT RULES OF ENGAGEMENT

• The site will be available until 4:00 PM

• Masks and maintaining a distance of at least 6 feet are required at all times

• Photographs of locations and equipment specific to this solicitation are authorized

• All information presented in tentative and subject to change

• No side bars or independent conversations between contractors and government personnel

• No discussions relating to other Corp acquisitions

• No corporate denigration or sabotage will be tolerated

• All questions must be submitted to ProjNet to obtain formal Government response

• Site visit attendee lists/presentations will be posted to beta.SAM

Presenter Presentation Notes

WORKLOAD:

This chart shows the Omaha District workload history from FY 12 to the present, and our projections for FY17. FY16 large spike due to VA-Aurora.

FY12 demonstrates the effects of the Missouri River flood event. FY13 reflects the impact of the furlough and the ripple effect among our customers. FY14 was subject to funding delays and natural disaster response (i.e., funding and response to FEMA Taskers for the Colorado natural disaster declaration (Sep 2013 Colorado Flood Event)).

WORKFORCE (August 2015):

Omaha Metro Area – 722 Field Offices – 519 Military officers/enlisted (10) CECI/ACE-IT, CPAC, Logistics Delivery Point, DA Interns, Contract Employees (71)

TOTAL – 1,322

FORT RANDALL DAM

MAJOR UNIT REHAB

JANUARY 12-13, 2021

HYDROELECTRIC DESIGN CENTER

BRITTANY HEFFERNAN, MECHANICAL ENGINEER

OUTLINE

• Site Work Completed in Preparation for the Major Rehab

• Turbine

• Plant and Unit Configuration

• Design Parameters

• Specific Design Concerns

– Shear Pins

– Alignment

• Miscellaneous Mechanical Scope

• Generator

• Existing Design

• Design Parameters/Specific Design Concerns

• SCADA Interface

WORK COMPLETED IN PREPARATION OF THE MAJOR REHAB

• Crane Rehabilitation including BTH/Lifting Devices

• GSU Transformers Procurement

• Bus/Cables

• Digital Governors

• Exciters

• Laydown Feasibility

PLANT AND UNIT CONFIGURATION

Two contracts used for Units 1-4 and Units 5-8

• Most characteristics are the same

• Different turbine shaft sizing

• Units 1-4 have 33” nominal dia.

• Units 5-8 have 34” nominal dia.

• Slightly different draft tubes

“Fast” and “Slow” Reacting Turbines

• Surge Tanks

• Odd units only

• Wicket Gate closure times

• Odd units close faster than even units

EXISTING TURBINE DESIGN PARAMETERS

Existing Turbines

• Units 5-8 shown

• Synchronous condensing

• Manufacturer: Allis-Chalmers

• Discharge Diameter: 186 inches

• RPM: 85.7 rpm

• Rated Head: 112 ft

• Rated Capacity: 57,500 hp

• Number of Buckets: 17

NEW TURBINE DESIGN PARAMETERS

• New Turbine Design Parameters

• Rated Net Head: 120 ft

• Rated Capacity: 71,200 HP **

• Guaranteed weighted prototype efficiency: minimum of 90.5%

• Cavitation: No visible cavitation in guaranteed operating region

• On-Site Considerations

• First unit completed on its own

• Followed by two units at a time

• Disassembly staggered

** Slides provided during the site visit indicated a rated capacity of 71,000 HP. Verbal correction was made during the site visit that the rated capacity is 71,200 HP, as stated in the solicitation specifications.

SPECIFIC DESIGN CONCERNS - TURBINE

• Shear Pin Failure Frequency

• Alignment

SHEAR PINS

• Frequently failing

• Averaging 2.5 failures per month

• Reported first in 1955

• High strength shear pins used

• Typical “failure” definition:

• Loss of air pressure, not a complete failure of shear pins

SHEAR PIN FAILURES – SPECIFICATION REQUIREMENTS

• Perform Wicket Gate Operating Mechanism Analysis

• Completed during model testing phase

• Provide recommendation to Government

• Analysis to include:

– Existing system analysis to include FEA

– Existing design field testing

– Existing shear pin material testing

– Final report and recommendation

• Optional items built in to contract to be exercised after analysis is complete -Intention is to refurbish wicket gates

ALIGNMENT

• Background

• Abbreviated alignment tests conducted on Unit 2

– Digital level, 4 dial indicators, no bearings removed (having uncertainty of roughly 0.0004 in/in or 0.002 degrees)

• Result

– Non-vertical Unit of 0.00122 in/in

(roughly 0.07 degrees)

• Solicitation requirements

• Re-establish stator center including re-doweling

• Re-leveling sole plates (Optional) if stator core replaced

MISCELLANEOUS MECHANICAL SCOPE

• Bearings

• Refurbish generator guide bearings (upper and lower)

• Refurbish turbine guide bearing

• Inspect and optionally refurbish thrust bearing shoes

• Provide self-lubricating bushings and bearing plates

• Refurbish wicket gate servomotors

• Refurbishment of main components:

• Headcover, operating ring, bottom ring, etc.

• Replace miscellaneous piping, valves, filters, strainers

• Provide vibration monitoring system

• Supply new oil

GENERATOR

Existing Generators

• Manufacturer: Westinghouse

• 115% Rated Power: 48,420 KVA

• Power Factor: 0.95

• Voltage: 13.8 kV

• RPM: 85.7 rpm

• Bore Diameter: 349.5 inches

• Wye Connected

• 486 five-turn multi-turn coils

• 6 parallel paths and 27 coils per parallel

SPECIFIC DESIGN CONCERNS - GENERATOR

• Uprate to 52 MVA at 13.8 kV

• Coil stator construction

• Prototype thermal cycling test

• Prototype voltage endurance testing

• Repair any minor stator core damage after test

• Refurbish any damaged field coils

• Stator Core

• Stator frame replacement if insufficient clamping force

• Stated potential design issues with core support leading to deformation – however, none observed at iron splits, typical all units

• Manufacture one core – if unused, install in final unit. If used, manufacture another so that one spare is always available

• Generator rotor mechanical

• Cast rotor spider construction

• No issues noted visually

• No issues noted from NDT

• Shaft Sizes

• U1 – U4 (built first)

• U5 – U8 are larger (built second)

• Generator Field

• Refurbish field coils as-needed based on test

• No tested issues at this time, all original

• Insulation is thermally capable of uprated condition

• If many require refurbishment, may execute optional CLINs to refurbish all

• Exciter

• Main is bypassed

• Full static digital rated to provide sufficient field for > 52 MVA machine

• Add exciter polarity reversing system

• Copper plate construction rated 1,250 Amperes

• Simple bus bar and stand-off insulator bolted construction with touch-safe enclosure on outside of generator air housing

• Re-use existing diesel locomotive cable (DLO cable)

• Will allow for easier removal of DLO cables to remove rotor

• Generator Leads

• Re-insulate main and neutral leads, silver-surface bolted connections, replace fasteners

• Clean, test, inspect, and replace as necessary standoff insulators and for 2,500 and 5,000 Ampere bus duct from generator terminals to 15kV cables

SPECIFIC DESIGN CONCERNS – SCADA INTERFACE

• Provide terminal boxes, power supply units, and meters

• Terminate points – interconnection by others

• PPCS is term for plant SCADA