RFP Attachment 1 - Statement of Work.pdf

STATEMENT OF WORK

FOR

ROOT CAUSE ANALYSIS FOR PES #7 TRANSFORMER

ARNOLD ENGINEERING DEVELOPMENT COMPLEX

ARNOLD AIR FORCE BASE, TENNESSEE 37389-9998

TABLE OF CONTENTS

1. SCOPE

1.1. General

1.2. Background

2. APPLICABLE DOCUMENTS

2.1. Government Documents

2.2. Non-Government Documents

3. REQUIREMENTS

3.1. Administrative

3.2. General Requirements

3.3. Design Requirements

3.4. Construction Requirements

SOW APPENDICES A through G

Appendix A – CSI Section Specifications

Appendix B – Test Reports

Appendix C– Oil Results

Appendix D – Fault Data

Appendix E – Drawings

Appendix F – Photographs

Appendix G – SHE Standards

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1. SCOPE

1.1. General: The Contractor shall perform a detailed on-site inspection, testing, engineering analysis, and report to determine the root cause for failure of a 161-kV, 192.258 MVA for 5 minutes, Tamini transformer, (with 33-position on-load tap changer) Serial Number 66826. Work also includes providing expert recommendations for repair of the existing transformer and input to design requirements for a new transformer. Work shall be performed by a factory trained technician or engineer and shall be overseen and reviewed by an independent Transformer Manufacturing Expert (TME). Contractor shall provide all labor, materials, plant, equipment, tools, supplies, electrical testing, temporary power, temporary lighting, portable lifting equipment, transportation, and oil spill contingency. Work shall be performed at Arnold AFB, TN.

1.2. Background:

1.2.1. PES Transformer #7 is the power source for a medium-voltage, uncontrolled, six-pulse rectifier. DC reactors (iron-core reactors located in the transformer tank and air-core reactors upstream of the rectifier) in the transformer's secondary circuit control the rectifier DC voltage output by means of the commutation overlap. The load on the rectifier is an electric arc.

1.2.2. A nearly identical transformer served this function previously. That transformer failed in a manner similar to PES Transformer #7 after 12 years of service.

1.2.3. The existing transformer was specified for a 25 year design life but failed after 5 years of service. The transformer failed while in service on 22 November, 2022.

The transformer was tripped off by the SEL-387 differential relay, the main tank Buchholtz relay, and the sudden pressure relay. The Buchholtz relay for the tap changer and diverter switch did not activate.

2. APPLICABLE DOCUMENTS

2.1. Government Documents

2.1.1. AEDC Safety, Health, and Environmental (SHE) Standards latest version, listed as requirements in Appendix A.1 and provided in Appendix G.

2.1.2. Code of Federal Regulations, latest version:

A. 40 CFR 279 Management of Used Oil.

B. 29 CFR 1928.1407/1408 Power Line Safety (up to 350 kV) – assembly and disassembly.

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2.2. Non-Government Documents

2.2.1. ASTM International:

A. ASTM D877-19 Standard Test Method for Dielectric

Breakdown Voltage of Insulating Liquids Using Disk Electrodes.

B. ASTM D923-15 Standard Practices for Sampling

Electrical Insulating Liquids

C. ASTM D924-15 Standard Test Method for Dissipation Factor (or Power Factor) and Relative Permittivity (Dielectric Constant) of Electrical Insulating Liquids.

D. ASTM D971-20 Standard Test Method for Interfacial

Tension of Oil Against Water by the Ring Method.

E. ASTM D974-21 Standard Test Method for Acid and Base

Number by Color-Indicator Titration.

F. ASTM D1275-15 Standard Test Method for Corrosive Sulfur in Electrical Insulating Oils.

G. ASTM D1298-17 Standard Test Method for Density, Relative Density (Specific Gravity), or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method-API Designation.

H. ASTM D1500-17 Standard Test Method for ASTM Color of

Petroleum Products (ASTM Color Scale).

I. ASTM D1524-22 Standard Test Method for Visual Examination of Used Electrical Insulating Oils of Petroleum Origin in the Field.

J. ASTM D1533-20 Standard Test Method for Water in

Insulating Liquids by Coulometric Karl Fischer Titration.

K. ASTM D1816-19 Standard Test Method for Dielectric

Breakdown Voltage of Insulating Oils of Petroleum Origin Using VDE Electrodes.

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L. ASTM D2945-03 Standard Test Method for Gas Content of Insulating Oils.

M. ASTM D5837-15 Standard Test Method for Furanic

Compounds in Electrical Insulating Liquids by High-Performance Liquid Chromatography (HPLC).

N. ASTM D6786-15 Standard Test Method for Particle Count in Mineral Insulating Oil Using Automatic Optical Particle Counters.

O. ASTM D7151-15 Standard Test Method for Determination of Elements in Insulating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES).

3. REQUIREMENTS

3.1. General: Comply with the job conditions and all safety requirements in Appendix

A.1, Job Conditions at AEDC. Specific safety concerns are identified as follows:

3.1.1. Compliance with Government approved Safety Plan. Safety Plan shall be in accordance with AEDC SHE Standard A6 with Supplement.

3.1.2. The inside of the transformer main tank is considered a confined space. Comply with AEDC SHE Std B5 and OSHA standards for confined spaces for work inside the tank. Phone the AEDC Fire Department dispatcher at 454-5648 prior to each confined space tank entry and at the conclusion of each entry. Submit a confined space entry plan 5 days prior to entering the tank.

3.1.3. Contractor shall provide lifting equipment for removal of components, cores and coils that is required prior to the task 4 work (untanking). Comply with AEDC SHE Standard D5. Submit a lift plan prior to performing lift. All work or repairs that require a crane to lift equipment or personnel shall comply with the provisions of 29 CFR 1926.1407 and 1408, which states that cranes may be used within a minimum clearance of 15-feet from energized 161kV and shall comply with the requirements of a critical lift. Refer to Appendix F for photographs showing the location of the transformer.

3.1.4. Perform work in accordance with AEDC SHE Standards B4 High Voltage

Electrical Work and B6 Low Voltage Electrical Safety Related Work Practices.

Obtain high voltage hold order from the Power Control Dispatcher for PES #7 transformer.

3.1.5. The Contractor shall provide all temporary power, environmental conditioning, and access control to a suitable, temporary structure for each stage of the work that will provide safe operation of the adjacent substation equipment and

Page-4 safeguard the existing equipment from environmental damage. The Government’s intent is to maintain all existing transformer components, core, clamping, tap changing, and other reusable equipment for future use.

3.1.6. The independent TME shall be available on-site to review and oversee all work.

3.2. Schedule and Outages

3.2.1. Submit request to the Government for outage 10 days after contract award.

3.2.2. Submit the Comprehensive Final Report that includes the RCA, all test reports, findings, and recommendations IAW CDRL.

3.3. Documentation, Communication and Reports:

3.3.1. Provide reports electronically at each stage of inspection and analysis and in accordance with CDRLs.

3.3.2. Conduct online conference calls with AEDC representatives to discuss findings and next steps in the analysis process. Facilitate online conference calls for the duration of the contract on a weekly basis, at a minimum.

3.3.3. All reports, analysis, designs, and repair shall be reviewed and signed signifying concurrence by an independent third-party Transformer Manufacturing Expert (TME). Submit findings in the following reports developed during sequenced tasks:

A. Fault Data Report.

B. On-Site Inspection and Testing Report.

C. Internal Inspection Report.

D. Comprehensive Report, with updates to the 1) Fault Data Report, 2) On-site Inspection and Testing Report, and 3) Internal Inspection Report.

3.4. Work Tasks: Work shall be sequenced in the four tasks as identified below.

Provide CDRLs and coordinate with the Government at the completion of each task.

3.4.1. Task 1 - Review the information from the pre-fault, fault, and post fault in the attachments, and provide a preliminary Fault Data Report, as to the nature of the fault. Prior to onsite work, Contractor shall:

A. Provide a plan to keep the existing transformer and components completely dry during testing and inspection. It is anticipated that a temporary shelter with roof and side walls will be necessary to cover the

Page-5 transformer. Submit Shelter Plan within 7 days after Notice of Award.

Temporary shelter shall be adequately secured to prevent unexpected movement due to wind. If a temporary shelter is placed within 40-feet of the existing 161kV bus the following precautions shall be taken:

1. Obtain high voltage hold order from the Power Control Dispatcher for the PES 161kV substation.

2. Ground the 161kV bus.

3. Disconnect the bus between the points “B2” shown on Elevation A-

A on Drawing 2011R1 in Appendix E.

4. Remove the couplings on each end of each task and remove the short section of bus of each task.

5. Save all removed pieces for reinstallation at completion.

3.4.2. Task 2 - As part of the on-site field analysis, inspect, test and evaluate all existing equipment associated with the transformer and document exact detail of the condition of the entire system. Submit On-site Inspection and Testing Report IAW CDRL. Under the direction of the TME, prepare the transformer and associated equipment for inspection and tests.

A. Disconnect the transformer as required, including all high voltage connections, medium voltage connections, isolate, ground, and lock out/tag out all energy sources in accordance with AEDC SHE Standards B4 and B6.

B. Perform detailed external inspection of transformer and components.

C. Complete thorough inspection and test of transformer before making any changes to transformer, draining oil, disassembling, or moving transformer.

D. Sample the oil from the main tank, diverter switch, and the on-load tap changer (OLTC) in accordance with ASTM D923. Provide a full set of dissolved gas analysis (DGA) of the oil in accordance with ASTM D2945.

Collect samples and provide analysis of the gas in the Buchholtz relay of the main tank, the diverter switch, and the OLTC. Submit test results

IAW CDRL.

E. The oil testing shall include but not be limited to the following tests:

Moisture in accordance with ASTM D1533, Interfacial Tension in accordance with ASTM D971, Acid Number in accordance with ASTM D974, Color Number in accordance with ASTM D1500, Visual in accordance with ASTM D1524, Dielectric Breakdown in accordance with ASTM D877 and D1816, Power Factor at 25C at 100C in accordance with ASTM D924, Specific Gravity in accordance with ASTM D1298, Corrosive sulfur in accordance with ASTM D1275, Furanic compounds in accordance with ASTM D5837, Metals in oil in accordance with ASTM D7151, and Particle count in accordance with ASTM D6786.

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F. Complete set of transformer test results: on all taps – winding resistance, ratio, Capacitance/Dissipation factor, Sweep Frequency Response Analysis, and core and electrostatic shield ground. The TME shall be on-site for the duration of the testing. Based on this information consider reduced voltage insulation resistance and additional tests as deemed necessary by the results of the previous tests and recommendations of the TME.

G. Test lighting arrestors for function (knee voltage) in addition to insulation resistance to confirm they were operational at time of failure.

H. Provide written comparison of the factory and field test report, oil results, and SEL event capture testing results to factory acceptance tests and maintenance test results in the Appendices B, C, and D.

3.4.3. Task 3 – Internal Inspection. Prepare transformer for disassembly and perform internal inspection.

A. Drain the existing oil from the transformer. Follow the oil down with dry air. The dry air shall have a dew point less than -50°C. Purge all air hoses with dry air to remove all moisture and dirt prior to use. Test dry air dew point after the equipment is set up and ready but before connecting to the transformer. Submit dew point test result prior to performing the work.

B. Handle and dispose of oil in accordance with 40 CFR 279.

C. Perform internal inspection using factory trained and qualified field engineer and technician. Document inspection and findings with photographs taken with Government provided camera. Photograph areas of damage.

D. Discuss findings with Government within 4 hours of completing the inspection.

E. Submit written Internal Inspection Report with detailed findings and any anomalies observed IAW CDRL.

F. The internal inspection shall include a condition report of the following:

1. All high voltage and low voltage bushing leads and lead structures.

2. Leads to the tap changer pass through barrier board.

3. Current Transformers (CTs) and associated mountings and wiring.

4. Tightness and integrity of all the coils.

5. Transformer core.

6. All high voltage and low voltage bushings leads.

7. Internal tank structure.

8. Reactor unit core, coils, leads, and connections.

9. Series unit core, coils, leads, and connections.

10. Photographs.

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3.4.4. Task 4: Inspection, Analysis and Comprehensive Report.

A. Disconnect the transformer as required, including auxiliary power, control cables and wires, and conduits. Clearly mark all cables and wires not already identified prior to disconnecting. Within 48 hours of completion, submit documentation of all wire and cable markings on the manufacturer’s Drawing TAD0200002383 provided in Appendix E.

B. Un-tank the existing main unit, series unit, and reactor core and coils and perform a detailed visual inspection and engineering analysis. The TME shall be on-site for the duration of the un-tanking to oversee and approve the work.

C. Clearly mark all leads and connections that are disconnected by use of indelible tags. Do not cut bolted connections without prior written approval of the Government Representative. The Government’s intent is to maintain all existing equipment and connections for future use. Carefully, safeguard all external and internal components from physical and environmental damage. Clearly mark all components, connectors, and leads removed or disassembled for future shipment.

D. Un-tank the load tap changer and diverter switch and perform a detailed visual inspection and engineering analysis.

E. Perform an assessment of the condition of the paper insulation on each leg of the main winding in 5 separate locations from the bottom of the winding to the top of the winding to determine any variation in level of paper deterioration. The samples shall include areas close to the hot spot fiber optic probe in each main winding. The paper insulation sampled should be located such that they are minimally impacted from the fault event to get the best assessment of the paper quality prior to the fault.

Include the results of the Degree of Polymerization Test with the Comprehensive Report.

F. A comprehensive report shall be submitted that includes:

1. Root Cause Analysis with detailed evidence and analysis documenting the probable cause of the failure, and identifying the specific operational, manufacturing or design defect.

2. Results of the Degree of Polymerization Test.

3. Updates to the previous reports (Fault Data, On-Site Inspection and Testing Report, and Internal Inspection Report).

4. Recommendations for preventing recurrence of failure, including design, operational or maintenance recommendations.

5. Recommendations for repairing the existing transformer, including an itemized list of component repairs and approximate cost.

6. Design requirements/specifications input for a new transformer with greater reliability and capability to perform under the

Page-8 anticipated operating conditions. The transformer should be designed such that when operated at 3,000 Amperes (ac) for 5 minutes, there will be a minimal loss of insulation integrity. The transformer shall be designed for a service life of 25 years.

7. Provide written evaluation of the existing transformer design and any recommendations for improving the transformer life and performance.

G. Submit a complete bound report of all work performed including all test results and engineering evaluation in one Comprehensive Report for the RCA of the transformer system. The report shall be reviewed and approved by the TME as indicated by their respective Professional Engineering seal/stamp prior to submitting for Government approval.

Submit five (5) hard copies and one electronic copy of the Comprehensive Report that includes all test reports and findings gathered during the investigation no later than 60 days after Notice of Award.

3.4.5. Upon completion of the work, prepare transformer for temporary storage at its present location. The preparation shall include:

A. Re-tanking the main unit, series unit, and reactor core and coils.

B. Re-tanking the load tap changer and diverter switch.

C. Securing each of the clamping frames to the tank.

D. Providing and securing blind flanges for every tank opening including piping connections, high voltage bushings, and medium voltage bushings.

E. After the tank has been re-assembled and all openings have been secured, furnish and install cylinders of nitrogen or bone-dry air with regulators and piping as necessary for (90) days of temporary storage of the transformer. Verify that the air in each cylinder has a dew point of - 50°C or less.

F. Test the transformer tank for leaks at a test pressure of 5 pounds per square inch and maintain the test pressure for at least eight hours with no oil leaks. Repair any leaks and document satisfactory test results.

G. Securing all removed components, assemblies, and piping previously removed for the RCA effort onto pallets. Co-locate all pallets of components with the transformer tank.

3.4.6. If the 161kV bus was previously removed, then:

A. Brush the ends of each piece of bus, reapply NO-OX compound, and properly torque the connectors when the bus pieces are reinstalled.

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B. Remove grounds and release the hold order upon completion.