W9127820R0018 AM01.pdf

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT 1. CONTRACT ID CODE PAGE OF PAGES

1 2

3. EFFECTIVE 4. REQUISITION/PURCHASE 5. PROJECT NO. (If applicable)2. AMENDMENT/MODIFICATION

NO. W9127820R0018-0001 26 FEB 2020

6. ISSUED BY CODE 7. ADMINISTERED BY(If other than item 6)

CODE

Corps of Engineers 109 St. Joseph St.

Mobile, AL 36602

8. NAME AND ADDRESS OF CONTRACTOR (No., street, county, State and ZIP code) 9A. AMENDMENT OF SOLICITATION

NO.

W9127820R0018

9B. DATED (SEE ITEM 11)

31 JAN 2020

10A. MODIFICATION OF

CONTRACT/ORDER NO.

10B. DATED (SEE ITEM 13)

CODE FACILITY CODE

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

The above numbered solicitation is amended as set forth in item 14. The hour and date specified for receipt of Offers is extended, is not extended. Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended, by one of the following methods: (a) By completing items 8 and 15, and returning copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted; or (c) By separate letter or telegram which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGEMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER. If by virtue of this amendment you desire to change an offer already submitted, such change may be made by telegram or letter, provided each telegram or letter makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

12. ACCOUNTING AND APPROPRIATION DATA (if required)

13. THIS ITEM APPLIES ONLY TO MODIFICATIONS OF CONTRACTS/ORDERS,

IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.

A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority)

THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE CONTRACT ORDER NO. IN ITEM 10A

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT ADMINISTRATIVE CHANGES (such as changes in paying office, appropriation date, etc.) SET FORTH IN ITEM 14, PURSUANT TO AUTHORITY OF FAR 43.103(b)

C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority)

E. IMPORTANT: Contractor is not, is required to sign this document and return copies to the issuing office.

14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible)

The subject solicitation for: Hartwell Powerhouse Rewind of Units 3&4, Hartwell, GA

Is modified in the following: REFER TO THE ENCLOSED ADDITIONAL SPECIFICATIONS FOR AMENDMENT NO. 0001

Except as provided herein, all terms and conditions of the document reference in item 9A or 10A, as Heretofore changed, remains unchanged and in full force and effect.

15A. NAME AND TITLE OF SIGNER (Type or print) 16A. NAME AND TITLE OF CONTRACTING OFFICE (Type or print)

15B. CONTRACTOR/OFFEROR

(Signature of person authorized to sign)

15C. DATE SIGNED 16B. UNITED STATES OF AMERICA

BY

(Signature of contracting officer)

16C. DATE SIGNED

NSN 7540-01-152-8070 30-105 STANDARD FORM 30 (REV. 10-83)

PREVIOUS EDITION UNUSABLE Prescribed by GSA

Unit 3 and 4 Generator Rewind at Hartwell Powerhouse in Hartwell, GA

W9127820R0018

SF 30 Page 2 W9127820R0018-0001

REVISIONS MADE BY ADDED AND/OR REPLACEMENT PARAGRAPHS/PAGES/SECTIONS

The items listed below are added or revised in the solicitation. Added sections are hereby made a part of the contract and are to be inserted in the proper numerical/alphabetical sequence.

ADDED SECTIONS

48 13 16.00 26 MISCELLANEOUS PARTS, MATERIALS, AND SERVICES

48 13 13.11 26 REWIND OF HYDRAULIC-TURBINE DRIVEN GENERATORS

REVISED SECTIONS

Section 01 00 01 paragraph 2 is revised to say Projnet questions shall be submitted no later than 3 April 2020 at 2:00 p.m. Central Time.

Hartwell U3 & U4 Rewind 19HA03

SECTION 48 13 13.11 26

MISCELLANEOUS PARTS, MATERIALS, AND SERVICES

PART 1 GENERAL

1.1 GENERAL INFORMATION

As the condition of the turbine/generator parts cannot be determined until each unit is disassembled, it is anticipated that work in addition to that specified in other SECTIONS may be required. This additional work will be directed in writing to be accomplished under an item or items in this section. Where work is specified in other SECTIONS to be accomplished under these items, no work shall be accomplished until the Government inspects the item and specific directions are given in writing. The unit prices to be charged for parts, materials and labor for additional work must not exceed the unit prices quoted in the Bid Schedule, which price must include the price for supervision, equipment, tools, labor, materials, transportation of items to and from the site to a repair workshop, overhead, and incidentals required for the work. The estimated quantities in the Bid Schedule for these items are for canvassing bids and more or less work than indicated may be required.

1.2 SUBMITTALS

1.2.1 General

Government approval is required for submittals with a "G" designation;

submittals not having a "G" designation are for information only. When used, a designation following the "G" designation identifies the office that will review the submittal for the Government. The following must be submitted in accordance with SECTION 01 33 00, "SUBMITTAL PROCEDURES":

1.2.2 Welding

See SECTION 05 05 23.20 26.

1.2.3 Non Destructive Inspection

See SECTION 05 05 33.20 26.

PART 2 PRODUCTS - NOT USED

PART 3 EXECUTION

3.1 MISCELLANEOUS WELDING (OPTIONAL)

Perform miscellaneous arc welding as directed. Qualification of welders and welding are specified in SECTION 05 05 23.20 26. The work may include the preparation of weld procedures, disposition of either mild steel or stainless-steel rod or wire, excavation of cracks in existing welds, manual stress relieving (if required), non-destructive testing of the welds, and finish grinding of the welded areas. The Contractor must furnish suitable scales and report forms for weighting and recording the amount of welding wire used. Gas shielding wire welding only is allowed inside the powerhouse, unless otherwise approved.

SECTION 48 13 13.11 26 Page 1

3.2 WELDING SERVICES (OPTIONAL)

Furnish the use of a welder with machine, leads and wire to perform miscellaneous welding, paragraph 3.1 "Miscellaneous Welding (Optional)", where payment by the pound under that bid item is not practical and payment by labor hours is determined to be more appropriate following written direction from the Government.

3.3 MACHINIST HIRE (OPTIONAL)

Furnish machinist and shop facilities to perform work on various equipment as directed.

3.4 ELECTRICIAN HIRE (OPTIONAL)

Furnish licensed electrician to perform work in the field on installation and repairs of various electrical machinery, equipment, and wiring as directed.

3.5 PAINTER HIRE (OPTIONAL)

Provide all labor, material, and equipment to perform painting in the field, as directed, to the generating unit, related equipment, and surrounding areas. Painting must include surface cleaning and preparation. Painters shall be qualified according to the requirements of

SECTION 09 90 00.01 26.

3.6 MILLWRIGHT HIRE (OPTIONAL)

Furnish a millwright to perform work in the fieldto the various parts and types of equipment.

3.7 GENERAL LABORER HIRE (OPTIONAL)

Furnish general laborer to perform miscellaneous work in the field pertaining to the repair of the unit as directed.

3.8 NON DESTRUCTIVE EXAMINATION (OPTIONAL)

Provide all labor, material and equipment to perform non destructive testing as directed in writing. Non-destructive testing includes visual, dye or liquid penetrant, magnetic particle, ultrasonic, and radiographic.

Methods and procedures of inspection are specified in SECTION 05 05 33.20 26.

3.9 MISCELLANEOUS PARTS AND MATERIALS

Repairs which are specifically directed in writing and not covered elsewhere in the specifications may require parts and materials which can only be determined after disassembly and inspection. Examples are fasteners, material for special fasteners, bronze bushings, materials for replacement components, etc. Repairs may also require equipment rental including items such as machine tool time. Repairs may also require the transportation of items to a repair facility. Invoices and signed purchase orders for reimbursement must be submitted under the Bid Item for "Transportation Services, Equipment Rental, Parts and Materials". Labor required for machining of bushings, special fasteners, etc. should be paid for under the appropriate Skilled Craftsman Hours Bid Item.

SECTION 48 13 13.11 26 Page 2

-- End of Section --

SECTION 48 13 13.11 26 Page 3

SECTION 48 13 16.00 26

REWIND OF HYDRAULIC-TURBINE DRIVEN GENERATORS

PART 1 GENERAL

1.1 GENERAL INFORMATION

This Section covers the following work at Hartwell Powerhouse Units 3 and 4:

a. Perform an electromagnetic finite element analysis of the proposed winding and core design to demonstrate that the design minimizes air-gap flux induced stator core vibrations at fundamental and harmonic frequencies

b. Analyze the existing frame for suitability for continued service with the new core, keybars, and core clamping system

c. Inspect and evaluate the stator frame sole plates, condition of the frame and sole plate interface and develop options to improve the fit and function as necessary, and verify torque of foundation anchors and hold-down bolts.

d. Design, manufacture, and perform voltage endurance testing on 4 prototype coils

e. Manufacture and perform thermal cycle testing on 5 prototype coils

f. Design, manufacture, shop test, prepare and load for shipment, deliver f.o.b. destination, and unload two complete sets of stator windings and all accessories

g. Remove stator windings, stator cores and stator core clamping systems

h. Furnish and install new circuit rings

i. Furnish and install new surge rings

j. Furnish and install new neutral current transformers

k. Furnish and install surge arresters

l. Furnish, install and test two new stator cores and core clamping systems

m. Install and test two new stator windings and accessories

n. Clean and inspect rotors, reinsulate rotor field leads, and test rotor field windings

o. Reinsulate rotor field leads

p. Furnish spare parts

q. Perform generator special field tests

SECTION 48 13 16.00 26 Page 1

r. At the optional of the Government, refurbish rotor poles

1.2 REFERENCES

The publications listed below form a part of this specification to the extent referenced. The publications are referred to in the text by basic designation only.

ASTM INTERNATIONAL (ASTM)

ASTM A 343 (2014) Standard Test Method for Alternating-Current Magnetic Properties of Materials at Power Frequencies using Wattmeter-Ammeter-Voltmeter Method and 25-cm Epstein Test Frame

ASTM A 717 (2012; R2018) Standard Test Method for Surface Insulation Resistivity of Single-Strip Specimens

ASTM A 720 (2002; R 2016) Standard Test Method for Ductility of Nonoriented Electrical Steel

ASTM D 1868 (2013) Standard Test Method for Detection and Measurement of Partial Discharge (Corona) Pulses in Evaluation of Insulation Systems

AMERICAN WELDING SOCIETY (AWS)

AWS A5.8/A5.8M (2012) Specification for Filler Metals for Brazing and Braze Welding

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

IEEE 43 (2013) Recommended Practice for Testing Insulation Resistance of Rotating Machinery

IEEE 56 (2016) Guide for Insulation Maintenance of Electric Machines

IEEE 95 (2002; R 2012) Recommended Practice for Insulation Testing of Large AC Rotating Machinery with High Direct Voltage

IEEE 115 (2009) Guide for Test Procedures for Synchronous Machines: Part I Acceptance and Performance Testing; Part II Test Procedures and Parameter Determination for Dynamic Analysis

IEEE 286 (2000; R 2012) Recommended Practice for Measurement of Power Factor Tip-Up of Electric Machinery Stator Coil Insulation

IEEE 1043 (1996; R 2009) Recommended Practice for Voltage-Endurance Testing of Form-Wound Bars and Coils

SECTION 48 13 16.00 26 Page 2

IEEE 1310 (2012) Recommended Practice for Thermal Cycle Testing of Form-Wound Stator Bars and Coils for Large Rotating Machines

IEEE 1434 (2014) Guide for the Measurement of Partial Discharges in AC Electric Machinery

IEEE 1553 (2002; R 2007) Standard for Voltage-Endurance Testing of Form-Wound Coils and Bars for Hydrogenerators

IEEE 1799 (2012) Recommended Practice for Quality Control Testing of External Discharges on Stator Coils, Bars, and Windings

IEEE C50.12 (2005; R 2010) Standard for Salient Pole 50 HZ and 60 Hz Synchronous Generators and Generation/Motors for Hydraulic Turbine Applications Rated 5 MVA and above

IEEE C57.13 (2018) Standard Requirements for Instrument Transformers

IEEE C57.13.1 (2016) Guide for Field Testing of Relaying Current Transformers

IEEE C62.11 (2012) Standard for Metal-Oxide Surge Arresters for Alternating Current Power Circuits (>1kV)

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

NEMA FI 1 (2004) Manufactured Electrical Mica

NEMA LA 1 (1992; R 1999) Surge Arresters

NEMA LI 1 (1998; R 2011) Industrial Laminating Thermosetting Products

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

NFPA 70 (2017) National Electrical Code

Occupational Safety and Health Act (OSHA)

54 CFR 2920 (1970) Williams Steiger Occupational Safety and Health Act

1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals having an "I" are for information only. Designation following the "G" or "I" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with Section 01 33 00, SUBMITTAL PROCEDURES.

SD-01 Preconstruction Submittals;

Within 60 calendar days after receipt of written notice to proceed

SECTION 48 13 16.00 26 Page 3

(NTP) with the rewinds:

Stator Winding Warranty Details; I, HDC

Stator Coil Facility; G, HDC

Stator Coil Voltage Endurance Test Facility; G, HDC

Thermal Cycling Testing Facility; G, HDC

Design Information on Surge Arresters; G HDC

Within 150 calendar days after receipt of written notice to proceed (NTP) with the rewinds

Stator Frame Analysis; G, HDC

Within 150 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Stator Design Review Meeting; I

Within 30 calendar days after receipt of written notice to proceed (NTP) with the core replacement:

Lamination Manufacturing Facility; G, HDC

SD-02 Shop Drawings

Include a parts list in shop drawings as appropriate.

Within 60 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Cross-Sectional View of Stator Coils; G, HDC

Exterior Dimensions of Stator Coils; G, HDC

Winding Diagram; G, HDC

Connection Details; G, HDC

Winding Bracing Configuration; G, HDC

Circuit Ring Configuration and Dimensions; G, HDC

Surge Rings; G, HDC

Main and Neutral Lead Details; G, HDC

Main And Neutral Lead Arrangement; G, HDC

Nameplate; G, HDC

Within 30 calendar days after receipt of written notice to proceed (NTP) with the core replacements:

Stator Core Laminations; G, HDC

SECTION 48 13 16.00 26 Page 4

Stator Core Vent Duct Spacers; G, HDC

Stator Core Completed Assembly; G, HDC

Lamination Die; I, HDC

Core Keybars; G, HDC

Stator Core Clamping System; G, HDC

Surge Arrester Drawing and Catalog Cut; G HDC

Surge Arrester Maintenance and Testing Manual; G HDC

Within 30 calendar days after the Government has exercised the option for rotor pole refurbishments:

(Optional) Rotor Pole Assembly and Details; G, HDC

(Optional) Rotor Pole Connections Assembly and Details; G, HDC

SD-03 Product Data

Within 60 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Stator Coil Insulation System; G, HDC

PDA System; G, HDC

Within 90 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

RTDs and RTD Extension Cable Catalog Cuts; G, HDC

Stator Assembly Materials and Dimensions; G, HDC

Current Transformer Catalog Cut; G, HDC

Within 120 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Spring Type Washers Loading; G, HDC

SD-05 Design Data

Within 90 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Wedging System Deflection Characteristics; G, HDC

DC I²R Copper Losses Design Calculations; G, HDC

Stray Load Losses Design Calculations; G, HDC

Maximum Temperature Rise; G, HDC

Temperature Rise Calculations; G, HDC

SECTION 48 13 16.00 26 Page 5

Within 60 calendar days after receipt of written notice to proceed (NTP) with the core replacements:

Core Losses Design Calculations; G, HDC

SD-06 Test Reports

Within 30 calendar days after the completion of the test:

Coil Test Record; G, HDC

Prototype Coil Voltage Endurance Test Report; G, HDC

Production Run Coil Voltage Endurance Test Report; G, HDC

Dissection and Examination Report; G, HDC

Prototype Coil Thermal Cycling Test Report; G, HDC

Coil Factory Test Report; G, HDC

Spring Type Filler Material Test Report; G, HDC

RTD Test Report; I, HDC

Lamination Test Report; G, HDC

PDA Test Report; G, HDC

Field Winding Final Test Report; G, HDC

Surge Arrester Conformance and Design Test Report; G HDC

SD-08 Manufacturer's Instructions

Within 60 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Voltage Endurance Test Methods; G, HDC

Thermal Cycling Test Methods; G, HDC

Coil Factory Test Procedure; G, HDC

Within 120 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Field Leads Reinsulation Procedure; G, HDC

Stator Winding Installation Procedure; G, HDC

Interlaminar Insulation Test Procedure; G, HDC

Initial Acceptance Test Procedures; G, HDC

Final Acceptance Test Procedures; G, HDC

Generator Special Field Tests Procedure; G, HDC

SECTION 48 13 16.00 26 Page 6

Post-Rewind Vibration Test Procedure; G, HDC

Within 30 calendar days after receipt of written notice to proceed (NTP) with the core replacements:

Lamination Test Procedure; G, HDC

Stator Core Keybars Installation Procedure; G, HDC

Within 30 calendar days after the Government has exercised the option for rotor pole refurbishments:

(Optional) Rotor Pole Removal and Reinstallation Procedure; G, HDC

(Optional) Pole Transportation Procedure; G, HDC

(Optional) Field Coil Reinsulation Procedure and Materials; G, HDC

SD-09 Manufacturer's Field Reports

Within 30 calendar days after the completion of the inspection or test:

Electromagnetic Finite Element Analysis of the Proposed Winding and Core Design; G, HDC

Stator Frame Sole Plate Inspection Report; G, HDC

Stator Frame Inspection Report; G, HDC

Stator Core Final Check Report; G, HDC

Interlaminar Insulation Test Report; G, HDC

Stator Winding Final Inspection Report; G, HDC

Winding Installation Test Report; G, HDC

Rotor Inspection Report; G, HDC

Initial Acceptance Test Report; G, HDC

Final Acceptance Test Report; G, HDC

Generator Special Field Test Report; G, HDC

Current Transformer Factory Test Report; G, HDC

Current Transformer Field Test Report; G, HDC

Rotor Pole Factory Test Report; G, HDC

SD-10 Operation and Maintenance Data

Within 120 calendar days after receipt of written notice to proceed (NTP) with the rewinds:

Spare Parts List; I, HDC

Within 30 calendar days after completion of generator commissioning:

SECTION 48 13 16.00 26 Page 7

Generator Operations and Maintenance Manual; G, HDC

1.4 EXISTING GENERATOR INFORMATION

1.4.1 Unit Identification and Nameplate

Hartwell Units 3 and 4 are outdoor, vertical hydro-generators, air cooled via water cooled radiators, manufactured by the Westinghouse Electric Company. The units were brought online in 1962. Generator ratings, as defined by the nameplate information, are as follows.

73,333 kVA

0.9 Power Factor

13,800 V 3-phase 60 Hz

100 RPM

115% continuous overload capability

The generator stators were rewound to 95,000 kVA by National Electric Coil (NEC) in 1999. The Westinghouse and NEC Generator field test reports are attached at the end of this section (attachments 1 and 2).

1.4.2 Description of Generator

The generators are designed for wye-connection of the stator windings with each phase consisting of nine (9) parallel paths of 15 coils, each with six (6) turns per coil. The stator core has 405 slots, a bore diameter of approximately 358.75 inches, and a height of 56.75 inches. The field windings are comprised of 72 field coils.

1.4.3 Background and History

1.4.3.1 Winding Failure

Unit 3 and 4 have a design flaw that caused stator noise and excessive vibration since they have been placed in service. Steps have been taken to correct the problems such as tightening the frame around the cores of both units at the time of their original commissioning and after rewind.

However, the efforts have had insufficient effect on the core vibration or sound level.

Unit 3 generator suffered a coil failure in August 2010 that forced the unit out of service. The failure was repaired and the unit was returned to service. Unit 3 stator failed again in 2013. The failure was repaired but the additional testing resulted in several coils that would need extensive work to isolate and repair. The work has halted. Unit 3 is currently out of service. These failures occurred at the point where the coil leads exit the coils in both cases. After the 2010 failure was repaired, end turn resonant frequency testing (exploratory impact) and core vibration testing was performed and measurements recorded. After the 2013 failure, multiple coils and pole jumpers were found with evidence of vibration induced insulation cracking.

1.4.3.2 Foundation Grout Cracking

Structural inspection of the sole plate system included sole plates, sole plate foundation anchoring, grout pad and concrete foundation surrounding

SECTION 48 13 16.00 26 Page 8 the grout pad was performed on Units 2, 3 and 4 in 2014.

Unit 4 inspection revealed the worst grout pad condition amongst the three units inspected. There were signs of large grout pad cracks and crushing, spalling, grout pad movement away from concrete foundation. Hammer tests performed on the grout pad revealed hollowness in all grout pockets except for small areas at the lower edge of grout pocket where the area is not subject to extensive stresses. The movement of grout pad away from concrete foundation was also evident which is more likely the result of thermal expansion/contraction forces transmitted through over-tight stator frame hold down bolts exaggerated by excessive vibration. The vibration has exaggerated these stresses causing additional cracks, crushing and hollowness of the grout pad.

Unit 3 inspection showed similar condition as Unit 4 with grout movement, cracks, crushing and hollowness of grout but to a lesser degree. The reason Unit 4 has worsened condition is because Unit 4 vibration intensity has been higher even though duration of vibration for Unit 3 has been shorter (according to project staff). This comparison between Unit 3 and 4 suggests that vibration has been contributing to grout pad degradation to a large degree.

In 2015, inspections revealed severe cracking and loosening of the grout under the stator frame sole plates of Unit 4. Vibration and air gap measurements were taken over a period of time and found to relatively stable though the vibration levels were high. Loose grout was removed, forms placed, and new grout injected into the damaged areas to restore the bearing surfaces. Subsequent inspections have revealed little additional grout cracking and the unit vibration level reduced after the repair.

1.4.4 Inspection by Contractor

The Government will make a generator available at the Contractor's request to permit the Contractor to inspect the generator and obtain dimensions required to design the replacement stator windings and cores. Coordinate the inspection schedule and access requirements with the Contracting Officer (CO). The generator rotor will not be removed for this inspection.

The existing core is continuously stacked in a three-section frame. The Contractor is responsible for obtaining and verifying dimensions and other information, including information contained in this specification, that may be required to design replacement stator windings and cores. Take measurements on the generator as necessary to ensure that coils and materials supplied under this contract will meet all contract requirements. A spare coil and a spare lamination are available at the powerhouse for measurement by the Contractor. The Government will not assume any responsibility for the accuracy of the dimensions of the coil.

Laminations from the existing cores will not be allowed to be removed for measurements before or after award. The Contractor is responsible for developing the necessary information required for design. Bring any discrepancies between information given in this document and information developed to the attention of the Government before proceeding.

1.5 WARRANTY

The warranty period for the complete installed windings is to be five (5) years after the successful completion of tests and acceptance. The Contractor is responsible for repairing or replacing any component failing to perform its function as specified and documented at no additional cost to the Government within the five (5) year period. Respond to the

SECTION 48 13 16.00 26 Page 9

Government and perform an assessment of the failure within four (4) weeks of the incident. Include disassembly and reassembly sufficient to make repairs, repair to any surrounding equipment as a result of the failure, and any necessary testing to confirm the efficacy of the repair. Replace any spare parts used during the repair in kind within one year of the completion of the repair. Submit for approval the Stator Winding Warranty Details, to include duration of warranty coverage and items and labor covered by the warranty.

1.6 FAILURE TO MEET PERFORMANCE GUARANTEES

Determine the measured combined stator DC I²R (copper) stray load losses and core losses in accordance with paragraph 3.33.2(a), Losses Tests.

Include the resistance of the circuit rings in the measured combined losses. Should the measured combined losses be greater than the guaranteed value and the Contractor fail to modify the winding within in a reasonable time to meet the loss guarantees and the winding be in otherwise satisfactory operational condition, the CO may accept the winding conditionally in lieu of pursuing other remedies allowed by the contract.

In that event, the Contractor must pay the Government or the Government will withhold any monies otherwise due in the amount of $4,400 per kW of measured combined losses above the loss guaranteed for each generator.

PART 2 PRODUCTS

2.1 MATERIALS

Conform all materials to the applicable specifications and standards listed and to the additional requirements specified herein. Obtain approval for the intended purpose of any materials required for the work, but not covered by the specifications, prior to the material incorporation. Reference to any equipment, article, or catalog number within this specification is to establish a standard of quality and not intended to limit competition.

2.2 DESIGN REQUIREMENTS

2.2.1 General

As part of the new winding and core design, perform an electromagnetic finite element analysis to demonstrate that the design minimizes air-gap flux induced stator vibrations at fundamental and harmonic frequencies.

The new winding and core design shall be optimized to avoid resonances between the winding harmonics and the core frame structure.

2.2.2 Final Report

Prepare and submit a final Electromagnetic Finite Element Analysis of the Proposed Winding and Core Design report of the findings and conclusions based on the analysis. Include documentation of the models developed, the analyses performed, the modified model results with proposed solutions implemented, and final recommended solutions.

2.2.3 Available Information

Review the available design drawings and test reports to develop models necessary for mechanical and electromagnetic analysis of the generator including the winding layout, the stator core and frame, including sole

SECTION 48 13 16.00 26 Page 10 plates and foundation attachments as necessary, the rotor poles, damper windings, and the airgap. The Government will provide access to drawings, previously performed test reports, and other readily available documents related to the design problems and investigations related to the existing winding and core vibration problem, if requested by the contractor.

Gather information sufficient to model the air cooling circuits if winding reconfiguration (pole group arrangement) resulting in an increase in field current requirements is offered as a recommended corrective measure.

2.3 ADDITIONAL REQUIREMENTS

(a) Analyze the existing frame for suitability for continued service with the new core, keybars, and core clamping system. Submit for approval Stator Frame Analysis report. At a minimum, the report shall include the following:.

1. Results of visual inspection of the frame structure and weldments

2. Evaluation that shows the frame can be used with the new core design

3. Frame dimensional and material inputs to a classical or FEA model for analysis that the frame can be adapted or used as is to adequately support the new core; that the frame can withstand the forces imposed on it by the new core clamping systems; and that the frame can adequately handle expected core expansion and contraction

(b) Inspect and evaluate the stator frame sole plates, condition of the frame and sole plate interface and develop options to improve the fit and function as necessary, and verify torque of foundation anchors and hold-down bolts. Perform inspection immediately after mobilization but prior to disassembling the unit. The report shall include an evaluation of the condition of the concrete, the grout, and the frame and soleplate interface. The report shall also contain options to improve the fit and function.

2.4 WINDING RATING AND INSULATION CLASS

Supply a stator winding rated no less than 95,000 kVA at 13.8 kV +/- 5%.

Provide stator coils and winding installation materials capable of operation at Class F temperature limits as defined in IEEE C50.12 . Design and provide a stator winding such that the temperature rise does not exceed 75°C above a cooler discharge air temperature of 40°C, when operated at rated load.

2.5 NAMEPLATE

Submit for approval the nameplate drawing. Include details on material, dimensions, and arrangement of information on the drawing. Make the nameplates of cast, stamped or etched brass or stainless steel similar in size and thickness to the original nameplates. Include the following information on the nameplates:

(a) Winding manufacturer's name

(b) Date of rewind

SECTION 48 13 16.00 26 Page 11

(c) Rated kVA

(d) Rated kV

(e) Power factor

(f) Stator current

(g) Stator temperature rise

(h)(h) Insulation class

2.6 STATOR COILS

2.6.1 General

Incorporate modern practice in design, material, and workmanship for the stator coils manufactured under this specification. Design coils to be the hard, multi-turn type with minimized eddy current loss. The voltage stress in the groundwall insulation shall not exceed 65 V/mil. Use annealed copper, free from splinters, flaws, rough spots, or short radius bends for the strands. Round all finished outside edges of each coil with a minimum radius of 1/16 inch. For the narrow side of the slot portion of each stator coil, provide a flat bearing surface of at least 3/8 inch. Do not cut or tailor any coil leads for any particular slot; design each coil for use in any slot. Submit the following for approval:

(a) Stator Coil Facility. The name, address and qualification of the stator coil facility.

(b) Cross-Sectional View of Stator Coils. A cross-sectional view of the stator coil in a stator slot, describing the stranding arrangement, strand dimensions, copper cross-sectional area, strand and turn insulation details (including insulating material types and thicknesses), slot fillers, wedging details, and partial discharge suppressive treatments. Include groundwall insulation materials and thickness on the drawing.

(c) Exterior Dimensions of Stator Coils. Include bending radii, dimensions of slot paint and grading tape on the drawing.

(d) Winding Diagram. A drawing that shows the three phases in different colors, coupling capacitors for the partial discharge analysis (PDA) system, and RTD locations. Include a tabular listing of the winding showing the progression from line end to neutral end for all parallels with the diagram.

(e) Stator Coil Insulation System. A description of the stator coil insulation system, including processes and materials employed to meet specification requirements. Include data sheets for materials used in the coil construction.

(f) DC I²R Copper Losses Design Calculations. Detailed design calculations demonstrating how the stator DC I²R (copper) losses are determined at 75°C. Illustrate with the calculations the composition of the various portions of winding circuit resistance, including number of coils in series, parallel connections, end connections, circuit rings, etc.

(g) Stray Load Losses Design Calculations. Detailed calculations showing

SECTION 48 13 16.00 26 Page 12 how the stray load loss is determined.

(h) Maximum Temperature Rise. Maximum temperature rise of the winding above 40°C ambient at rated load, voltage, and power factor.

(i) Temperature Rise Calculations. Calculated stator winding temperature rise as indicated by embedded temperature detectors and calculated stator winding hot spot temperature at rated load, voltage, and power factor. Correlate the relationship between the operating "hot spot" temperature of the stator coils and the temperature measured by RTD demonstrated by direct measurement or recognized methods of calculation to special factory tests on a basically similar machine.

2.6.2 Coil Design

2.6.2.1 Conductor Strand Insulation

Make strands continuous (splice free) within the entire mean turn length of each coil. Insulate strands with continuous filament glass, dacron-glass fibers, or mica tape, bonded to the copper with a suitable bonding agent. Size and arrange conductor strands to minimize eddy and circulating current losses.

2.6.2.2 Turn Insulation

Insulate each turn with multiple layers of mica tape in combination with suitable backing materials. Turn insulation may be applied to individual strands in lieu of dedicated turn insulation, or alternative methods for insulating turns may be employed, as approved by the CO.

2.6.2.3 Ground Insulation

Provide ground insulation that consists of multiple overlapped layers of mica tapes applied continuously throughout the entire length of the coil to achieve an equal thickness. Meet the requirements of NEMA FI 1 , Table 5-2 for the mica tape. Use mica tapes constructed with a glass or polyester fabric backing material. Apply a suitable protective covering tape over the ground insulation mica tape.

2.6.2.4 Coil Consolidation

Bond the slot and end winding portions of the assembled strands into a homogenous structure of controlled size using heat and pressure. Use strand bonding resins with properties and characteristics to prevent bond failure due to the mechanical, thermal, and chemical effects associated with thermal cycling while operating within the Class F temperature limits for which the winding is to be designed.

2.6.3 Coil Manufacturing Methods

2.6.3.1 Vacuum Pressure Impregnation (VPI)

After drying treatments, completely fill the coil insulation with a solventless epoxy resin using a vacuum pressure impregnation process.

After impregnation, cure the coil insulation system by the application of heat and pressure to the slot and end winding portions of the coils. Size slot portions to closely controlled dimensions and restrain end portions with suitable pressure devices to ensure a well-compacted insulation structure. No internal voids, as determined by the COIL DISSECTIONS in

SECTION 48 13 16.00 26 Page 13 paragraph 3.4, are allowed in the insulation between the copper strands and the outer edge of the stator coils in the slot portion and under the grading tape of the stator coils, including those coils subjected to the Voltage Endurance tests as described in paragraph VOLTAGE ENDURANCE TESTS.

2.6.3.2 Resin Rich Tapes

Resin rich, B stage, or loaded tapes may be used in lieu of the resin impregnation process. Cure the coil insulation system by the application of heat and pressure to the slot and end winding portions of the coils.

Size slot portions to closely controlled dimensions and restrain end portions with suitable pressure devices to ensure a well-compacted insulation structure. No internal voids, as determined by the COIL DISSECTIONS in paragraph 3.4, are allowed in the insulation between the copper strands and the outer edge of the stator coils in the slot portion and under the grading tape of the stator coils, including those subjected to the Voltage Endurance tests as described in paragraph VOLTAGE ENDURANCE

TESTS.

2.6.4 Finish and Partial Discharge Suppression Treatment

Treat slot portions of the stator coils, and a suitable distance beyond, with a semiconductive compound capable of giving positive electrical contact between the treated portions of the coil surface and the entire length of the core slot walls. Design this semiconductive treatment to eliminate surface discharge (corona) between the coil and slot surfaces and between top and bottom coil sides.

2.6.5 Graded Suppression Treatment

Apply a voltage grading semiconductive tape to the stator coil surface extending outward from the semiconductive treatment. Apply the voltage grading semiconductive tape to be of a length and resistivity to limit coil surface voltage gradients to levels well below corona onset levels under normal operating voltage stresses at normal operating temperatures.

During a black-out test at 9.2 kV, as described in paragraph 3.26(d), Blackout Test, no visible corona is allowed to be produced by the winding.

Treat coil surfaces beyond the discharge suppressive treatments with a finish capable of resisting exposure to dampness, oil vapors, Contractor-recommended cleaning solvents, or other materials to which the winding may be exposed during operating life.

2.6.6 Coil Test Record

Give each coil a unique identification. Keep a permanent Coil test record for each coil, whether the coil is included in the finished winding or not. Include the results of all coil tests and the slot number where each coil has been installed in this record.

2.6.7 Prototype Coils

Use entire coils for prototype stator coils, complete with all armor tapes and stress control materials applied. Omit materials normally bonded to the coil that are used to secure the coil in the slot. Manufacture prototype coils to be identical to those manufactured under paragraph

STATOR COILS.

SECTION 48 13 16.00 26 Page 14

2.6.8 Quantity

(a) Prototype Coils. Prior to manufacturing the production run coils, manufacture at least the following quantities of prototype coils. Also manufacture any additional coils which may be required due to failure.

Four (4) stator coils for voltage endurance testing Four (4) stator coils for thermal cycling testing One (1) stator coils for thermal cycling control testing

Do not manufacture the production run coils before the prototype coils are tested and dissected and the test report is approved.

(b) Production Run Coils. Following the approval of the prototype coil testing and dissection, provide 6 production run coils, plus any additional coils which may be required due to failure, for the Voltage Endurance testing specified in paragraph VOLTAGE ENDURANCE TESTS. Do not use or provide as spares coils subjected to Voltage Endurance testing in the final winding. Provide sufficient coils to make up two complete windings. Also supply the spare coils listed in paragraph

SPARE PARTS.

If the manufacturing of the first and second set of coils takes more than 2 months apart, provide another set of 6 production run coils, plus any additional coils which may be required due to failure, for the Voltage Endurance testing.

2.7 RESISTANCE TEMPERATURE DETECTORS (RTDs)

Supply for installation in the stator winding of each unit twenty-four

(24) 3-wire resistance temperature detectors (RTDs) suitable for operation in a Class F insulation system. Provide 100 ohm platinum RTDs (±0.12% at 0°C) with a TCR of 0.00385 ohm/ohm/°C. Supply RTDs with a semiconductive coating on the body. Supply and locate RTDs in accordance with clause 7.3 of IEEE C50.12 . Replace existing RTD extension wires to the generator terminal cabinet with new extension wires. Use No. 16 AWG tinned stranded copper, three-conductor cable immune to electrical noise for RTD extension wires. Use oil and water resistant cable with an overall metallic armor for mechanical protection. Polyvinyl chloride (PVC) will not be allowed.

RTD leads must be solder-spliced to the RTD extension wires outside the stator slot. Do not use mechanically spliced leads. Splices are not allowed within the slot portion. Submit RTDs and RTD Extension Cable Catalog Cuts.

2.8 FILLERS, WEDGES, TIES, AND BLOCKING MATERIAL

2.8.1 General

Provide materials suitable for use in conjunction with a Class F winding insulation system for use in the stator slots, such as fillers, wedges, ties and blocking.

2.8.2 Stator Assembly Materials and Dimensions

Submit for approval a description of materials used for the assembly of the stator coils in the generator core. Include all end-bracing and blocking materials, wedging, filler, and brazing materials. Include drawings detailing the dimensions of all wedges and fillers used in the stator.

SECTION 48 13 16.00 26 Page 15

2.8.3 Side Packing

Systems using a non-spring-type filler inserted in the slot after inserting the coil are not acceptable. Use one of the following side packing systems:

(a) Apply a semiconductive silicone rubber compound to the sides of the coil and cure before insertion. Form an interference fit between the silicone rubber and the sides of the slot.

(b) Apply a semiconductive coil wrapper in conjunction with conducting putty continuously applied throughout the length of the slot.

(c) Drive a ripple spring between one side of the coil and the slot to form an interference fit. Submit the acceptable ripple spring deflection.

2.8.4 Center and Bottom Filler

Fabricate center and bottom fillers from semiconductive materials. Provide semiconductive material impregnated throughout and not coated on top of an insulating backing. Provide a center filler between the two coil sides in a slot sized to prevent interference between the top and bottom coils in the straight part extension. In specified slots, install RTDs in place of the center filler. Use bottom filler between the bottom coil side, or furthest from the center of the bore, and the bottom of the slot.

2.8.5 Spring-Type Filler Material

Install spring-type filler material between the top filler and the wedge.

2.8.6 Wedges and Top Filler

Manufacture slot wedges from NEMA LI 1 Grade G11 material with a cross-sectional shape to match the groove shape of the stator laminations and provide a snug, sliding fit when placed in position in the slot.

Include a wedge cutback at the cooling air passages designed to enhance the air flow. Furnish top fillers of various thicknesses to ensure acceptable radial wedging pressures. Furnish a top filler of at least

0.020 inch for use against the coil. Provide a locking system for restricting the possible axial movement of the wedges. Furnish three check wedges per slot, located at quarter points in the slot. Design check wedges with no less than five (5) holes to measure spring-type filler deflection. Upon completion of the wedging, all wedges along the length of the slot must be independently tight in the slot.

2.8.7 Two-Part Wedges

If using a two-part wedging system, assemble the wedges and slides using a master slide to select the correct slide thickness. Provide slide lengths that neither project above the top of the wedge nor touch the wedge below.

Install all wedges so that all slides are driven from above.

2.8.8 Wedging System Deflection Characteristics

Submit the wedging deflection characteristics for approval including:

(a) Initial deflection of slot wedging spring-type filler and radial

SECTION 48 13 16.00 26 Page 16 pressure applied to the stator coils in slot portions.

(b) Minimum acceptable deflection of the slot wedging spring-type filler after extended operation and the radial pressure applied to the stator coil at the minimum acceptable deflection.

(c) Calculations to show that the radial pressure wedging system forces must exceed the non-fault condition forces throughout the life of the winding. Calculate forces at rated load, voltage, power factor and at worst fault condition.

2.8.9 End Winding Bracing and Blocking Material

End winding bracing material consists of resin-impregnated conforming materials, blocks, and glass twine. Use Dacron felt thoroughly impregnated with resin for conforming material between the coils. Use glass-based blocks when the space cannot be filled with the conforming material.

Saturate all ties with resin during and after installation.

2.9 CIRCUIT RINGS AND STATOR CONNECTIONS

2.9.1 General

Provide circuit rings, complete with all necessary connections, taps, adapters, braces, supports, and materials for making line and neutral connections between the winding, the terminals of the phase buses, and the terminals of the neutral current transformer bus assembly. Provide drawings of the Connection Details including coil-to-coil connections, jumper connections, connections from coils to circuit rings, details of any external transpositions and connections from the circuit rings to the main and neutral leads, Winding Bracing Configuration, and Circuit Ring Configuration and Dimensions.

2.9.2 Electrical Configuration

Design the stator windings to be wye-connected, with each phase of the stator winding consisting of multi-turn coils with neutral leads and the common main lead brought out within the generator housing at their existing location.

2.9.3 Physical Construction

Design the circuit rings, supports, and connecting leads for installation in the same general location as the existing equipment, without alteration of the air baffling system or modification of structural parts. Do not use more than twelve pieces to make up each circuit ring. Braze all factory joints in accordance with the requirements of AWS A5.8/A5.8M . Manufacture circuit ring blocking from NEMA LI 1 Grade G11 material.

2.10 SURGE RINGS

Provide upper and lower stainless steel surge rings. Insulate the surge rings for 15kV with full class F insulation. Submit for approval a drawing of the surge rings including dimensions and material.

2.11 MAIN AND NEUTRAL LEADS

Replace the main and neutral leads. Silver surface all bolted connections and make connections using Belleville spring-type washers with stainless

SECTION 48 13 16.00 26 Page 17 steel fasteners, or approved equal. Submit calculations to demonstrate the adequacy of the Spring Type Washers Loading. Design and supply main and neutral lead supports to firmly maintain the connections in place. Provide Main and Neutral Lead Details and Main and Neutral Lead Arrangement drawings.

2.12 PDA SYSTEM

2.12.1 General

Furnish partial discharge analysis (PDA) systems for units 3 and 4. Submit for approval the PDA system. The submittal should provide installation instructions, coupling capacitor details, coupling capacitor location and mounting, termination panel details, termination panel location, and coaxial cable routing and mounting.

2.12.2 Coupling Capacitors

Furnish and install two (2) coupling capacitors per phase for each winding. Provide coupling capacitors capable of withstanding the DC and AC high potential generator tests.

2.12.3 Leads

Furnish Sufficient leads to go from the coupling capacitors to the termination panel. Use RG58A/U coaxial cable for the leads. Terminate each lead with a BNC connector.

2.12.4 Termination Panel

Size each termination panel to accommodate all coaxial cable leads, BNC connectors, terminal boards, and termination and protective devices.

Terminate each coaxial cable with a 1.5 kilo-ohm, 1 watt, non-inductive resistor and a gas discharge surge arrestor at the rear of the BNC.

2.12.5 Analyzer

Provide a portable partial discharge analyzer specifically designed and equipped for use with the permanently installed capacitive couplers.

Furnish an Iris Power Engineering Inc. model PDA-IV, or approved equal, for the analyzer unit. Include the following features:

(a) The PDA differential amplifier rejects system noise, amplifies the partial discharge pulses, and sorts them with respect to magnitude, polarity, and phase.

(b) The analyzer provides printouts of the monitored activity.

(c) Provide all cables and connectors required for connecting the analyzer with the BNC panel and with a high-speed oscilloscope.

(d) Provide with the analyzer a partial discharge analyzer tester, a test guide for operating personnel, an instruction manual for maintenance personnel, a standard operating spares kit, and a transit case.

(e) Bandwidth of no less than 350 MHz (at 3 dB down).

(f) Data display in 3-D (three axis) format.

SECTION 48 13 16.00 26 Page 18

(g) Equipment connected to all six (6) connectors simultaneously.

(h) An accessory to extend the dynamic range for testing individual coils.

2.13 STATOR CORE MATERIALS

2.13.1 Stator Core Laminations

Provide drawings of the Stator Core Laminations and Stator Core Vent Duct Spacers including dimensions, materials and tolerances. Submit an assembly drawing of the Stator Core Completed Assembly, including dimensions and tolerances, for the completed stator core.

(a) Furnish the required number of new laminations to completely stack the new stator cores, continuously without splits. Make the laminations from high-grade non-aging silicon steel. Submit for approval Core Losses Design Calculations based upon design factors including, but not limited to, the proposed lamination steel and stacking factor. The new core losses (in kW) shall be lower than or equal to the existing core losses.