Attachment_1_-_KN6A_and_KN8A_Transformer_Rehabilitation_Specification_May92021.pdf

U.S. Department of the Interior SPECIFICATIONS Bureau of Reclamation Lower Colorado Dams Office Boulder City, Nevada April, 2020

Hoover Dam Powerplant Rehabilitate Six (6) 100 MVA Single Phase Transformers at Hoover Dam

Boulder Canyon Project, Arizona, Nevada

140R3021R0019 – Attachment 1 Dated: May 9, 2021

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FOREWORD

The transformers are physically located on the downstream ramp of Hoover Dam.

Hoover Dam is approximately 8 miles northeast of Boulder City, Nevada and 32 miles from Las Vegas, in Clark County, Nevada.

The six transformers are each a single-phase transformer two banks of three. Each single-phase transformer is rated for 100MVA giving a rating of 300MVA for the bank. The transformers were manufactured by SMIT-NYMEGEN between 1985 and 1990. The transformers are located outside and are in the vicinity of the Colorado River. Each transformer holds 7200 gallons of oil. The transformers are class FOW (Forced Oil and Water).

Hoover is seeking a contractor to replace the items and parts listed in this document to bring the transformers back to reliable operation for 20 or more years. Hoover performs periodic power factor testing of all the generator step up transformers. Hoover also performs dissolved gas analysis testing on the transformers. The tests on the transformers show them to be in good condition. The goal is to maximize the life of these transformers by replacing ancillary equipment.

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Contents

1. GENERAL

1.1 Abbreviations

1.2 Transformer Details

1.3 Requirements

1.4 Period of Performance

1.5 Schedule

1.6 Government furnished Equipment, Utilities and Facilities

1.7 Liquidated Damages

1.8 Security / Clearances

1.9 Safety

1.10 Hazardous Materials

1.11 Protection of Existing Installations and Structures

1.12 Final Acceptance of Work

1.13 Special Work Permit

1.14 Access to the Construction Work Area

1.15 Government Submittal Review

1.16 Drawings

2. TECHNICAL REQUIREMENTS

2.1 Specifications

2.2 Testing

2.3 Bushings

2.4 Spare Transformer Bushings

2.5 Current Transformers

2.6 Instrumentation, Controls, and ancillary devices

2.6.1 Low Voltage Winding Temperature Gauge

2.6.2 High Voltage Winding Temperature Gauge

2.6.3 Oil Temperature Gauge

2.6.4 Buchholz Relay

2.6.5 Sudden Pressure Relay

2.6.6 Oil Flow Indicators

2.6.7 Fault Monitor / DGA

2.6.8 Oil Level Indicator

2.6.9 Rupture Bladder Indicator

2.6.10 Hot Spot Detectors

2.7 Tank Oil Valves

2.8 Oil Motors and Pumps

2.9 Heat Exchangers

2.10 Conservator

2.10.1 Air System

2.10.2 Dehydrating Breather

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2.10.3 Cleaning of Conservator Tank

2.11 Tank Penetration and additional Gasket Replacement

2.12 Conduit and Wiring Replacement

2.13 Transformer Tank Cleaning

2.14 De-energized Tap Changer Maintenance

2.15 Oil Processing

2.16 Inspection

2.19 Option to Install Rapid Tank Depressurization

2.18 Welding of DBI SALA Base Plate on Top of Transformer

2.19 Tolerances of Newly Supplied Items

2.20 Technical Manuals

2.21 Technical Support

2.22 Reference Drawings

3. SUBMITTALS

4. SMIT Operation and Maintenance Manual

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1. GENERAL

1.1 Abbreviations

A. The following is a list of abbreviations used through-out this document with definitions.

USBR: United States Bureau of Reclamation MVA: Mega Volt Ampere kV: kilovolt OSHA: Occupational Safety and Health Administration CO: Contracting Officer COR: Contracting Officer’s Representative Hz: Hertz BIL: Basic Impulse Level RSHS: Reclamation Safety and Health Standards IEEE: Institute of Electrical and Electronics Engineers FOW: Forced Oil and Water

1.2 Transformer Details

The contractor shall provide the personnel, equipment, and materials to rehabilitate six (6) 100 MVA Single Phase transformers (KN6A and KN8A) at Hoover Dam.

KN6A and KN8A are generator-step-up transformers with 16.5kV low side and 230 kV high side.

1.3 Requirements

Contractor is required to supply all material necessary to perform the following work on these transformers KN6A-A,B and C phases and KN8A-A,B and C phases:

Bushings:

Replace H1 Bushings on six transformers Replace 2 H1 Current Transformers on six transformers Replace 1 H1 Current Transformer for winding Temp simulation on six transformers

Replace X1 and X2 bushings on six transformers Replace 2 X1/X2 Current Transformers on six transformers Replace 1 X1/X2 Current Transformer for winding temp simulation on six transformers

Replace H2 Bushing on six transformers

Instrumentation:

Replace X Winding Hot Spot Detector on six transformers Replace Dial type thermometer for X windings temperature on six transformers

Replace H Winding Hot Spot Detector Detector on six transformers Replace Dial type thermometer for H windings temperature on six transformers

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Replace Oil Temperature Gauge and Probe on six transformers Replace Dial type thermometer for oil temperature on six transformers

Replace Item 41,42,46,47 in SMIT Part List on six transformers

Controls and ancillary devices:

Replace Buchholz Relay on six transformers Replace Gate Valves – between Conservator and Buchholz Relay on six transformers Replace Gate Valves on Both Sides of Buchholz Relays on six transformers Replace Gate Valves – between Buchholz Relay and tank on six transformers

Pressure Relief Device:

Replace Pressure Relief Devices on six transformers

DGA Monitor:

Replace Fault Monitors with DGA monitors on six transformers Replace Globe Valve for Fault (Hydrogen) Monitors on six transformers

Tank:

Replace Gate Valve Oil Outlet Tank #1 on six transformers Replace Gate Valve Oil Inlet Tank #1 on six transformers Replace Gate Valve Oil Inlet Tank #2 on six transformers

Oil Pumps, motors, and valves:

Replace Pump #1 Oil Flow Indicators on six transformers Replace Gate Valves Oil Inlet #1 on six transformers Replace Oil circulating pump #1 and motor #1 on six transformers

Replace Pump #2 Oil Flow Indicators on six transformers Replace Gate Valves Oil Inlet #2 on six transformers Replace Oil circulating pump #2 and motor #2 on six transformers

Heat Exchangers:

Replace Heat Exchanger #1 on six transformers Replace Gate Valve Oil Outlet on six transformers Replace Gate Valve Water Inlet on six transformers Replace Gate Valve Water Outlet on six transformers

Replace Heat Exchanger #2 on six transformers Replace Gate Valve Oil Outlet on six transformers Replace Gate Valve Water Inlet on six transformers Replace Gate Valve Water Outlet on six transformers

Conservator:

Air System Replace Conservator Bladder on six transformers Replace Air Vent on six transformers Replace Alarm relay “rupture bladder” on six transformers Replace Globe Valve – Top of Conservator on six transformers Replace Dehydrating Breather on six transformers

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Process and Re-use Oil on six transformers Replace Gate Valve - Filling conservator on six transformers Replace Globe Valve – Filling pipe on six transformers Replace Oil Level Gauge on six transformers

Tank Penetrations and Gaskets – Replace the following gaskets on six transformers:

Top:

HV Bushing HV Manhole for connection HV Manhole for CTs HV Oil Return Near top of HV Bushing penetration

LV Bushing – X1 LV Bushing – X2 LV Manhole for connection for CT LV Side Hatch Cover 1 LV Side Hatch Cover 2 LV Oil Return

Pressure Relief Device Oil Pipe to Conservator

H0 Bushing Oil Pipe to cross pipes Blind Flanged Opening

Side:

Top Fault Monitor Oil Return H0 Bushing Manhole Capped Valve Upper Filter Valve

Bottom Tap Changer Manhole Capped Valve Lower Filter Valve with sampling device Oil Inlet Oil Inlet

Electrical Lines to be replaced for six transformers:

Conservator Oil Level Gauge Line Conservator Bladder Rupture Alarm Relay Buchholtz Relay Oil flow indicator 1 Oil Flow indicator 2

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Power to Pump 1 Power to Pump 2 High Voltage Current Transformer (3 total per transformer) Low Voltage Current Transoformer (3 total per transformer) High Voltage Winding Temperature Low Voltage Winding Temperature Oil Temperature

Place vacuum on transformer tank according to manufacturer guidelines prior to filling with oil.

Process Oil to remove contaminants, moisture and dissolved gases from the transformer oil.

Contractor shall provide scaffolding and ladders necessary to access areas of the transformer for this work. Contractor is responsible for modifications to the scaffolding for the duration of this work. All metallic ladders and metallic scaffolding shall be grounded at any point where there is an electrical break in the scaffolding. The base of the scaffolding shall be grounded and any points of the scaffolding where the electrical and magnetic circuit is broken in relation to the base. There are conductors near the base of the transformer where ground connections can be made. The COR will show the contractor where the ground connections are. Please use caution and verify the ground connections are ground connections before making connections. The ground connections are bare copper wire protruding from the concrete under the transformers.

1.4 Period of Performance

A. The overall period of performance is 360 calendar days. Outage season at Hoover Dam occurs between October 1 and May 30. The individual outages for the two transformers will be in this timeframe.

B. KN6A - The contractor shall have 30 calendar days to do all the field work on KN6A.

During the outage season for this transformer, a hazardous energy clearance will be placed. The timeline begins after the clearance is set and the transformer is available for the contractor to sign onto the clearance. When the contractor removes their lock from the clearance, the transformer shall ready to be put into service.

C. KN8A - The contractor shall have 30 calendar days to do all the field work on KN8A.

During the outage season for this transformer, a hazardous energy clearance will be placed. The timeline begins after the clearance is set and the transformer is available for the contractor to sign onto the clearance. When the contractor removes their lock from the clearance, the transformer shall ready to be put into service.

1.5 Schedule

A. Daily Work Hours. The work shall be done during normal work hours (6:30 a.m. to 5:00 p.m., Nevada time)– Monday thru Friday.

B. Holiday, Overtime, Night work or Weekend work may be available and requires approval from the Contracting Officer 48 hours prior.

C. Project Schedule - The contractor shall submit schedules for work on both transformers. This schedule can be one document provided it shows the start and end dates for work on these transformers.

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D. KN6A – Outage

1. Overall schedule including parts and equipment acquisition

2. Field work installation schedule during outage for the transformer

3. Testing and commissioning of all parts replaced during this work

E. KN8A – Outage

1. Overall schedule including parts and equipment acquisition

2. Field work installation schedule during outage for the transformer

3. Testing and commissioning of all parts replaced during this work

See section 3 for submittal schedules.

1.6 Government Furnished Equipment, Utilities and Facilities

A. Available Electrical

1. 480VAC, 3Φ is available for use at the contractor’s discretion. If used, the contractor is responsible for connections and power distribution in the work area.

2. 110VAC, single phase is also available for limited amperage use

B. Roadway access

1. Due to hairpin turns, access via lower portal road is limited to utility trucks and shorter flatbed delivery trucks.

2. The cable way crane will be used for equipment and material that cannot be delivered by truck to the job site. Contractor shall make necessary arrangements to use the cradle used with the cable way crane. USBR employees will make determination if equipment can be lowered via the cable way crane. This is dependent on how the load is stabilized. The contractor shall provide all necessary strapping to hold load during transit.

1.7 Liquidated Damages

Liquidated damages will be incurred at $1,000.00 per day past the end of the period of performance.

1.8 Security / Clearances

A. For all on site work, all contractor personnel working on site shall be subject to passing background investigations and be cleared prior to commencement of work. It shall be the contractor’s responsibility to incur costs for the credentialing process.

B. The contractor will be required to furnish a list of all employees (prime and subcontractors) who have passed background investigations and will be working at the site(s).

C. The following identifies the requirements:

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1. CONTRACTOR EMPLOYEE SECURITY REQUIREMENTS. Operations at Hoover Dam, and their power-plants, require continuous and effective security measures. In accordance with Homeland Security Presidential Directive-12, all on-site Contractor personnel shall have a Government-issued Personal Identity Verification credential before being allowed access to work at the site.

2. The cost of initiating the credentialing process, submitting the requisite forms, obtaining fingerprints, travel to a Credentialing Center for card enrollment and activation, and security interviews shall be borne by the Contractor.

3. The cost of suitability and PIV related background investigations will be borne by the Government.

4. For each employee who will be working at Hoover Dam the Contractor shall complete the highlighted portion of the Request for Initiation of Contractor Background Investigation form and all Declaration for Federal Employment Forms (OF-306) and Fair Credit Authorization Forms. Failure to complete the forms timely may cause delays in processing background investigations.

5. Promptly mail (do not e-mail or fax) the completed forms to:

Andy Trader (LCD-23203) Hoover Dam PO Box 60400 Boulder City, NV 89006-0400

6. Following the submittal of the above investigation package for each employee, the employee will receive an invitation to provide additional information required for their background investigation through the on-line e-QIP process. The background investigation will be conducted by the Office of Personnel Management, with the results furnished to the Reclamation Office of Security, Safety, and Law Enforcement for final determination of the employee’s suitability to be assigned to a Reclamation facility.

7. Once a favorable determination has been made, Contractor personnel shall be invited to visit the Reclamation Credentialing Center at:

Lower Colorado Regional Security Office 200 Date Street Boulder City, NV 89005

(702) 293-8008

8. Contractor personnel may have the option of visiting a more convenient location to complete the enrollment process.

9. The Contractor shall be responsible for ensuring that its employees comply with all required investigation interviews and established security rules and regulations.

10. Contract personnel shall not be permitted to enter established or designated restricted areas unless so authorized by the Government. Entry shall be in accordance with and

Rev. 1 – Rapid Tank Depressurization - 2/26/2021 140R3021R0019 subject to the security regulations established in the area. It shall be the Contractor’s responsibility to ensure that its personnel do not enter these areas unless authorized.

11. The Personal Identity Verification Card must be obtained from, and returned to, the Hoover Dam Police Department at the completion of on-site work.

1.9 Safety

A. The Contractor shall comply with all federal, state and local laws and standards as well as the current version of the Bureau of Reclamation manual Reclamation Safety and Health Standards (RSHS).

B. The Contractor may also download or view the electronic version of the RSHS manual at no charge from the Bureau of Reclamation web site at:

C. For the onsite work, the contractor shall perform and submit a Job Hazard Analysis to:

1. Identify safety hazards

2. Determine methods to mitigate and eliminate those hazards.

3. All onsite personnel shall read, understand and sign the Job Hazard Analysis.

D. The contractor shall ensure all areas are cleaned and maintained in neat and orderly manner.

E. Each morning, the job foreman shall conduct an on-the-job or toolbox safety meeting and all employees under their supervision must attend.

F. The contractor shall report accidents, injuries, or illnesses in accordance with Reclamation Safety and Health Standards, Section 3.5.

G. The contractor must remove employees who refuse or repeatedly fail to comply with safe work practices and standards, or supervisors who fail to enforce compliance.

H. Some Existing Hazards to be aware of:

1. Electrical hazard - Work is in the vicinity of 230 kilovolt lines that will be energized. Proper distances must be maintained around live circuits. Please refer to OSHA Section 1910.269 for minimum approach distances to energized circuits.

2. Fall hazard while working on top of transformer.

3. Fall hazard while working on transformer deck. The transformers are located on a shelf next to the roadway. The elevation of the shelf above the roadway is approximately 4 feet. Care must be taken when working in the area.

4. Trip Hazard – on road next to transformer ramp. Rails are embedded in the concrete, and care must be taken when walking on this road.

5. In the case of a fire alarm, drill or actual fire, all contractor personnel working at Hoover will report to the Arizona ramp adjacent to Unit A3 transformer and provide a head count to the Government Contracting Representative (the inspector). Personnel will not return to

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1.10 Hazardous Materials

A. The Contractor shall be responsible for chemicals, grout, sealant, or other pollutants that are released into the air, drainage system of the dam, or into the river. The contractor shall ensure precautions are taken at the work site to contain potential hazardous material release into the Colorado River.

B. Waste material shall be removed and properly disposed of in approved and legal manners.

C. Costs of disposal of the bushings, gaskets, non-used hardware and any additional material shall be included with the bid amount. Old bushings shall be disposed according to government regulations. Any transformer oil that is not re-used shall be disposed according to current environmental regulations. All costs of disposal of bushings and oil shall be paid by contractor. These costs shall be included in the total bid price.

D. The contractor is responsible for proper and legal disposal of all waste materials, oils and solvents according to hazardous waste disposal regulations.

E. Contractor shall manage disposal of all removed equipment and shall arrange to have all parts disposed of according to environmental regulations. Contractor is prohibited from disposing of removed material in trash containers managed by Hoover.

F. Contractor shall have oil absorbent pads on-site to handle small oil spills. Contractor is responsible for disposing of oil-soaked material in accordance with environmental regulations.

Disposal of oil-soaked material using dumpsters and trash containers at Hoover is prohibited.

G. Contractor is required to submit a Hazardous Material Control Plan prior to starting work due to the hazards involved with handling transformer oil. The Hazardous Material Control Plan must be approved by the government before this work may take place.

Approximately four weeks will be needed by the government to review the plan. Work performed shall comply with the Resource Conservation and Recovery Act. The plan shall address items listed below.

H. The contractor shall submit an oil spill plan and reporting procedures.

I. The contractor shall maintain onsite the technical data sheet and SDS sheet for material used on site.

J. All diverted waste should be tracked using FORM E: Waste Diversion Table and submitted to the COR.

K. The contractor shall remove all unused material; tools, debris.

L. Contractor shall submit a list including quantities of all chemicals brought to the work site. This list shall be approved prior to start of work.

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M. Contractor shall complete a waste manifest for all chemicals removed from the facility. This shall account for chemicals used during work and any chemicals that were not used. The government shall receive a copy of this manifest at the time the chemicals are shipped from the job site.

1.11 Protection of Existing Installations and Structures

A. The contractor shall safeguard the existing facilities and equipment from any harm resulting from their operations by using enclosures, drop cloths, coverings, etc. Any materials necessary to provide protection of existing facilities and equipment will be furnished by the contractor, remains the property of the contractor, and upon completion of the work, will be removed from the facility area by the contractor.

B. The contractor shall repair, at the contractor’s expense, any damage to property caused by the contractor’s action or by failure of the contractor to adequately protect the property. If the contractor fails to make such repairs in a timely manner, the Government may elect to repair the damage and to charge the contractor the cost of repair.

C. Any damage to historical property must be restored to original condition within a time frame as coordinated with the contracting officer or contracting officer’s representative not to exceed one year. The contractor shall repair, at the contractor’s expense, any damage to existing installations due to the contractor’s failure to provide proper protection. The Government may exercise the option to repair any such damage and charge the contractor for the cost at the discretion of the Contracting Officer.

1.12 Final Acceptance of Work

A. An inspection will be conducted by the Government at the completion of all work.

When the work has been completed, inspected, and accepted, final payment for the work will be authorized.

B. Clean up shall be inspected by Government and completed to the Governments satisfaction before final payment is made.

1.13 Special Work Permit

A. The contractor will be required to sign and abide by the instructions in a special work permit spelling out the allowed Dam and powerhouse areas for the contractor.

B. This special work permit will also identify any unusual hazards that might exist in the construction areas. The special work permit will also include any clearances required for safe completion of work.

1.14 Access to the Construction Work Area

A. The Contractor shall coordinate and plan for access to the installation area with the Government.

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B. The Contractor shall not block traffic with parked vehicles, equipment, and/or materials. Additional area for the Contractor’s use shall be provided at an area near the warehouse.

C. The Contractor shall place identification labels, with the Contractor’s name, on the windshield of their vehicles parked at any location on the Hoover Dam site. This shall not be required if the Contractor’s name is prominently displayed at some other location on the vehicle.

1.15 Government Submittal Review

A. The government will have the opportunity to review all submittals and provide feedback. The government will be allowed 16 calendar days to review and provide feedback on a submittal. If a submittal is found deficient, the government will send notice to the contracting companies representative stating the deficiency and will suggest a solution to remedy the deficiency. If the contractor does not act to correct the deficiency, the contract may be delayed until a solution is agreed to. If a submittal is deemed deficient, the government will have another 16 days to review the modified submittal. A submittal found deficient will require correction or modification before it will be considered approved.

1.16 Drawings

A. Provide updated drawings of all installed equipment. The drawings shall show physical location of the item on the transformer along with electrical wiring and connections to the control cabinet located on the transformer.

2.0 Technical Requirements

2.1 Specifications

A. Contractor shall review and use the following standards for the planning, installation and commissioning of all parts and labor associated with this work. The standards are:

IEEE C57.12.00 – General Requirements for Liquid Immersed Distribution, Power and Regulating Transformers

IEEE C57.12.10 – Requirements for Liquid Immersed Power Transformers

IEEE C57.12.80 – Terminology for Power and Distribution Transformers

IEEE 64-1969 – Guide for Acceptance and Maintenance of Insulating Oil in Equipment

IEEE Std 637 – IEEE Guide for the Reclamation of Insulating Oil and Criteria for Its Use

IEEE Std 1276 – IEEE Guide for the Application of High-Temperature Insulation Materials in Liquid-Immersed Power Transformers

IEEE Std 1538 – IEEE Guide for Determination of Maximum Winding Temperature Rise in Liquid-Filled Transformers

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IEEE Std C57.12.10 Cor 1 – IEEE Standard Requirements for Liquid Immersed Power Transformers

IEEE Std C57.12.10 Cor 2 – IEEE Standard Requirements for Liquid-Immersed Power Transformers

IEEE Std C57.12.70 – IEEE Standard Terminal Markings and Connections for Distribution and Power Transformers

IEEE Std C57.12.90 – IEEE Standard Test Code for Liquid-Immersed Distribution, Power and Regulating Transformers

IEEE Std 57.13 – IEEE Standard Requirements for Instrument Transformers

IEEE Std C57.13.1 – IEEE Guide for Field Testing of Relaying Current Transformers

IEEE Std C57.19.01 – IEEE Standard Performance Characteristics and Dimensions for Outdoor Apparatus Bushings

IEEE Std C57.19.100 – IEEE Guide for Application of Power Apparatus Bushings

IEEE Std C57.91 – IEEE Guide for Loading Mineral Oil Immersed Transformers

IEEE Std C57.93 – IEEE Guide for Installation and Maintenance of Liquid-Immersed Power Transformers

ANSI/IEEE 57.94 – IEEE Recommended Practice for Installation, Application, Operation and Maintenance of Dry-Type General Purpose Distribution and Power Transformers

IEEE Std C57.96 – IEEE Guide for Loading Dry-Type Distribution and Power Transformers

IEEE Std C57.98 – IEEE Guide for Transformer Impulse Tests

IEEE Std C57.100 – IEEE Standard Test Procedure for Thermal Evaluation of Liquid-Immersed Distribution and Power Transformers

IEEE Std C57.104 – IEEE Guide for Interpretation of Gases Generated in Oil-Immersed Distribution and Power Transformers

IEEE Std C57.105 – IEEE Guide for Application of Transformer Connections in Three-Phase Distribution Systems

IEEE Std C57.106 – IEEE Guide for Acceptance and Maintenance of Insulating Oil in Equipment

IEEE Std C57.109 – IEEE Guide for Liquid-Immersed Through Fault Current Duration

ASME B16 – Valves, Flanges, Fittings and Gaskets

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2.2 Testing

A. Contractor shall perform power factor tests on the bushings before and after installation, along with tests of the transformer to verify the transformer can be put back in service after work is completed.

B. Transformer tests shall include but not be limited to power factor, winding insulation resistance, core megger testing, exciting current tests, bushing power factor testing, sweep frequency response analysis (SFRA) and dissolved gas analysis.

C. Tests shall be done before the start of work by the contractor and after work is complete by the contractor. The results of these tests may be compared with previous test data obtained by BOR personnel at Hoover and the comparison may determine whether the transformer can/should be put back in service. Contractor to provide pre tear down test results to COR before rehabilitation work may begin.

D. Contractor to perform current transformer turns ratio tests, insulation resistance and polarity tests for all current transformers being replaced.

E. Copies of the test results will be supplied to the COR when completed. The copies shall be printed hard copies.

2.3 Bushings

A. The bushings being replaced will be supplied by the contractor.

B. Contractor will proceed to install the new bushings with gaskets and hardware and connect them to the transformer.

C. Contractor shall supply crane with operator, oil processor, oil holding tank/tanks, oil containment and all tools necessary to perform the required work.

I. H1 Bushing

1. The high side bushings designated H1 shall be replaced with new bushing manufactured by ABB. These bushings do not require higher temperature rating. The new bushings shall have porcelain insulation and shall be gray. The bushings shall be rated for operating voltages at or above 230kV and shall meet IEEE standards. Each bushing shall have a power factor test tap. These bushings shall be rated for outdoor use and shall be weather resistant. These bushings are used in an oil filled transformer. The bushing shall be capable of use in 60 Hz power transmission and have a BIL rating of 1050kV. The rated current for this bushing shall be 800 Amps. Refer to SMIT drawing 3961 C896 for bushing dimensions and details.

II. X1 and X2 Bushings

1. Bushings shall be replaced with new bushings manufactured by ABB. The voltage rating for this style of bushing shall be 25kV. The low side bushings shall be constructed with 125 degrees Celsius insulation and shall be made of porcelain. This is a high temperature feature available from ABB. The porcelain shall be gray. These bushings will meet IEEE

Rev. 1 – Rapid Tank Depressurization - 2/26/2021 140R3021R0019 standards. These bushings shall be rated for outdoor use and shall be weather resistant. These bushings are used in an oil filled transformer. The bushing shall be capable of use in 60 Hz power transmission and have a BIL rating of 150kV. The rated current for these bushings shall be 7500 Amps. Refer to SMIT drawing 3944 C678 for bushings dimensions and details.

III. H2 Bushing

1. Neutral bushing shall be replaced with a new bushing manufactured by ABB and shall be made of porcelain. This bushing does not require higher temperature rated insulation. The porcelain shall be gray. These bushings shall meet IEEE standards. Each bushing shall have a test tap. These bushings shall be rated for outdoor use and shall be weather resistant. These bushings are used in an oil filled transformer. The bushing shall be capable for use in 60 Hz power transmission and have a BIL rating of 150kV. The rated current for this bushing shall be 1200 Amps. Refer to SMIT drawing 3945B357 for bushing dimensions and details.

2.4 Spare Transformer Bushings

A. Contractor to supply one (1) 230kV bushing for use in these transformers. The spare bushing will have a bolt pattern that will attach to the single-phase SMIT-Nymegen transformers and will have ratings addressed in IEEE standards for this style of bushing. The bushing shall be kept in original manufacturer crating and delivered to the Hoover Dam warehouse for storage.

Contractor is responsible for the bushing until received at the warehouse. This bushing shall be manufactured by ABB and shall be made of porcelain. The bushing shall be filled with oil and ready for use by USBR when necessary. This will be a spare bushing for the six SMIT- Nymegen GSU transformers at Hoover. This bushing shall have a test tap and be capable of use in an oil filled transformer. Refer to SMIT drawing 3961 C896 for bushing dimensions and details. The spare bushing shall have identical ratings to the one’s installed.

B. Contractor to supply one (1) 25kV rated neutral bushing for use in these transformers. The spare bushing will have a bolt pattern that will attach to the single-phase SMIT-Nymegen transformers and will have ratings addressed in IEEE standards for this style of bushing. The bushing shall be kept in original manufacturer crating and delivered to the Hoover Dam warehouse for storage. Contractor is responsible for the bushing until received at the warehouse. This bushing shall be manufactured by ABB and shall be made of porcelain. The bushing shall be filled with oil and ready for use by USBR when necessary. This will be a spare bushing for the six SMIT-Nymegen GSU transformers at Hoover. This bushing shall have a test tap and be capable of use in an oil filled transformer. Refer to SMIT drawing 3945B357 for bushing dimensions and details. The spare bushing shall have identical ratings to the one’s installed.

C. Contractor to supply two (2) spare 25kV low side bushings for use in these transformers. These spare bushings will have a bolt pattern that will attach to the single-phase SMIT-Nymegen transformers and will have ratings addressed in IEEE standards for this style of bushing. These bushings shall be kept in original manufacturer crating and delivered to the Hoover Dam warehouse for storage. Contractor is responsible for these bushings until received at the warehouse. These bushings shall be manufactured by ABB and shall be made of porcelain. These bushings shall be filled with oil and ready for use by USBR when necessary.

These will be spares for the six SMIT-Nymegen GSU transformers at Hoover. These bushings

Rev. 1 – Rapid Tank Depressurization - 2/26/2021 140R3021R0019 shall have a test tap and be capable of use in an oil filled transformer. Refer to SMIT drawing 3944 C678 for bushing dimensions and details. These bushings do require a higher temperature rating. The spare bushings shall have identical ratings to the one’s installed.

2.5 Current Transformers

A. Bushing mounted current transformers shall have the following ration and metering and relaying classes:

1. H1 Top current transformer will have a ratio of 1200:5 and be class C800.

2. H1 Bottom current transformer will have a ratio of 1200:5 and be class C800.

3. X1 current transformer will have a ratio of 6000:5 and be class C800.

4. X2 current transformer will have a ratio of 6000:5 and be class C800.

5. H1 winding hot spot detector current transformer shall be rated for the contractor supplied hot spot detector. The hot spot detector and current transformer shall be a matched set.

6. X1 winding hot spot detector current transformer shall be rated for contractor supplied hot spot detector. The hot spot detector and current transformer shall be a matched set.

B. Current transformers shall be suitable for use in oil.

C. Current transformers shall fit over current transformer pockets of newly supplied and installed transformer bushings.

2.6 Instrumentation, Controls and Ancillary Devices

2.6.1 Low Voltage Winding Temperature Gauge

A. Replace total quantity six (6): The existing temperature gauge is manufactured by Qualitrol, 104 Series with four (4) normally open contacts per gauge. The temperature range for this gauge is 0 to 160 degrees Celsius. The replacement gauge shall have the same number and type of contacts and shall have the same temperature scale. This gauge shall read “Low Voltage Winding Temperature”. The casing of the gauge shall be ANSI 70 light gray. The low voltage winding temperature electrical contacts shall be wired into the existing wiring located on the transformer. These devices shall be rated IP56 or higher and be rated for outdoor use. The dial gauge with contacts shall be housed in a metal casing to meet the IP56 requirement. This gauge shall have a resettable indicator for highest temperature obtained. This temperature gauge shall be a capillary type thermometer.

2.6.2 High Voltage Winding Temperature Gauge

A. Replace total quantity six (6): The existing temperature gauge is manufactured by Qualitrol, 104 Series with four (4) normally open contacts. The temperature range for these gauges is 0 to 160 degrees Celsius. The replacement gauges shall have the same number and type of contacts and shall have the same temperature scale. This gauge shall read “High Voltage

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Winding Temperature”. The casing of the gauge shall be ANSI 70 light gray. The high voltage winding temperature electrical contacts shall be wired into the existing wiring located on the transformer. These devices shall be rated IP56 or higher and shall be rated for outdoor use. The dial gauge with contacts shall be housed in a metal casing to meet the IP56 requirement. This gauge shall have a resettable indicator for highest temperature obtained. This temperature gauge shall be a capillary type thermometer.

2.6.3 Oil Temperature Gauge

A. Replace totally quantity of six (6): The existing oil temperature gauge is manufactured by Qualitrol 104 series with 1 normally open contact. The replacement temperature gauge shall be rated IP56 or higher and shall be rated for outdoor use. The temperature gauge shall come equipped with a minimum of 1 normally open contact. The gauge shall read from 0 to 120 degrees Celsius and shall be marked “Liquid Temperature”. The casing of the gauge shall be ANSI 70 light gray. The oil temperature gauge electrical contacts shall be wired into the existing wiring located on the transformer. The casing for the dial shall be metal to meet the IP56 requirement. This gauge shall have a resettable indicator for highest temperature obtained. This temperature gauge shall be a capillary type thermometer.

2.6.4 Buchholz Relay

A. Replace total quantity six (6): The existing buchholz relays are manufactured by EGEM type 9 (BF 80/10). This device has one normally open contact that closes when excessive gas is detected. The new device will have the same mechanical mounting configuration and the same style contact. The new device shall be wired into the existing detection circuit on the transformer. This device shall be rated for outdoor use.

B. Replace total quantity twelve (12): The two (2) three inch gate valves on both sides of the buchholz relay shall be replaced with new gate valves. The two new valves shall be in inches (metric is not acceptable). The new valves shall be made of the same material as the existing.

This will include gaskets used around the valves and buchholz relay. The gaskets shall be the same type as the ones removed.

2.6.5 Sudden Pressure Relay

A. Replace total quantity six (6): The existing pressure relief devices are manufactured by Qualitrol type 208-002-04 + SWT 612-1. Contractor shall supply a new pressure relief device that mates with the existing opening of the transformer. The new pressure relief device shall have a minimum of one (1) normally open contact that closes when the pressure rises. The new sudden pressure relief device shall have a flag showing when the device activates. This device shall be rated for outdoor use.

2.6.6 Oil Flow Indicators

A. Replace total quantity twelve (12): The existing oil flow indicators are made by Qualitrol type FLA 644-2 + CAS 664-2. The new flow indicators shall be labeled “Oil Flow Indicator”. It shall also have the following labels “Pump On” and “Pump Off” with the correct indication represented by a dial. The oil flow indicators shall be rated IP56 or higher and shall be rated for outdoor use. The case shall be constructed of die cast aluminum with an ASA #70 thermosetting powder coat finish. The indicator shall have a UV stabilized polycarbonate lens

Rev. 1 – Rapid Tank Depressurization - 2/26/2021 140R3021R0019 securely fastened in place with stainless steel bezel ring and hardware. The casing shall be metal to meet the IP56 rating.

2.6.7 Fault Monitor / Dissolved Gas Analyzer

A. Replace/Install total quantity six (6): Fault monitors ( Hydran 201R Gas Monitors) are presently installed on the transformers. The outputs of the gas monitors have been disabled due to nuisance tripping. There is also an isolation valve in front of both gas monitors. The contractor will replace the isolation valve in front of the gas monitors with a similar style globe valve and install new gas monitors. The new gas monitors shall have the ability to detect the following gases: Hydrogen (H2), Oxygen (O2), Methane (CH4), Carbon Monoxide (CO), Carbon Dioxide (CO2), Ethylene (C2H4), Ethane (C2H6), Acetylene (C2H2) and Nitrogen (N2).

This device shall be rated IP65 or higher. These devices shall be rated for outdoor use. A remote screen shall be located near the main control box on the transformer that shows the amount of each of these gases. The screen shall be ultraviolet resistant and shall show each gas for a minimum of five seconds and no more than ten seconds before scrolling to the next gas percentage. A keypad shall be included allowing an operator to scroll through the screen display at their convenience. The screen and keypad shall be located approximately 4-5 feet above the concrete pad for the transformer to allow easy viewing for personnel. The fault monitor shall have the ability to measure moisture in oil. The monitor shall have a 7 inch color LCD screen.

The monitor shall have a two enclosure design. The monitor shall use photo-acoustic spectroscopy (PAS) for gas measurement. The frequency of gas measurement shall be adjustable from once per hour to once every week and shall come with a rapid mode to obtain a sample in 30 minutes. The monitor shall have an IP56 compliant enclosure.

B. Contractor to replace the 2 inch globe valve used to isolate the fault monitor. The new valve shall be the same type and material as already installed on the transformers. This will include installation of necessary gasketing.

2.6.8 Oil Level Indicator

A. The existing oil level indicator is made by Qualitrol model 042-001-CS 5394. A new oil level indicator will be installed and will have one normally open contact that will close with a decrease in oil level. The contact shall be rated for operation of 24 to 220 volts either alternating current or direct current. The maximum switching current will be 2 amps. The oil level gauge shall have a 6 inch dial face with a UV resistant polycarbonate lens. The level indicator shall have a die cast aluminum housing with a thermosetting powder coat finish. The oil level indicator shall be magnetically coupled. The casing for the indicator shall be metal and shall meet IP56 requirements.

2.6.9 Rupture Bladder Indicator

A. The rupture bladder indicator shall be replaced with a similar style that can be installed without allowing air to enter. Contractor shall be responsible for finding a suitable replacement.

2.6.10 Hot Spot Detectors

A. Contractor to replace hot spot detectors named 49TRH (H1-winding) and 49 TRX (X1 winding) with 100 ohm platinum detectors. These detectors will be used with existing

Rev. 1 – Rapid Tank Depressurization - 2/26/2021 140R3021R0019 current transformers. The existing H1 current transformer has a ratio of 800:4 with a 15VA rating. The existing X1 current transformer has a ratio of 6000:4 with a 15VA rating. The housing for these detectors and related devices shall be rated IP56 or higher. The enclosures shall be metal.

2.7 Tank Oil Valves

A. All valves supplied shall have ASTM and ANSI ratings. The valves shall be standard sizing and thread. Metric valves are not permitted. The valves sizes shall match what is listed below for sizing and shall mate with supplied heat exchangers and transformer connections.

B. One 3 inch gate valve with gaskets for the Buchholz relay on the conservator side of the relay. SMIT Item No. 61. Replace on six transformers.

C. One 3 inch gate valve with gaskets for the Buchholz relay on the tank side of the relay.

SMIT Item No. 62. Replace on six transformers.

D. One 2 inch globe valve with gaskets on top of the conservator. SMIT Item No. 64.

Replace on six transformers.

E. One 1 inch gate valve with gaskets and an adapter to 1 inch NPT filling valve for the conservator. SMIT Item No. 65. Replace on six transformers.

F. One 1 inch globe valve with gaskets in the filling pipe for the conservator. SMIT Item No. 67. Replace on six transformers.

G. One 1 inch utility valve with gaskets located on the top cover of the transformer.

SMIT Item No. 96. Replace on six transformers.

H. One 2 inch globe valve with correct adapter for new fault (dissolved gas) monitor.

SMIT Item No. 97. Replace on six transformers.

I. One 2 inch upper filter valve with gaskets. SMIT Item No. 100. Replace on six transformers.

J. One 2 inch lower filter valve with gaskets and oil sampling port. SMIT Item No. 101.

Replace on six transformers.

K. Two (2) five inch gate valves with gaskets for oil inlet to tank. SMIT Item No. 130.

Replace on six transformers.

L. One 4 inch gate valve with gaskets for oil outlet to tank. SMIT Item No. 131.

Replace on six transformers.

M. One 2-1/2 inch gate valve with gaskets before pump number 1. SMIT Item No. 211.

Replace on six transformers.

N. One 2-1/2 inch gate valve with gaskets before pump number 2. SMIT Item No. 212.

Replace on six transformers.

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O. One 2-1/2 inch gate valve with gaskets after heat exchanger number 1. SMIT Item No. 221. Replace on six transformers.

P. One 2-1/2 inch gate valve with gaskets after heat exchanger number 2. SMIT Item No. 222. Replace on six transformers.

Q. One 2 inch gate valve for the water inlet on heat exchanger number 1. SMIT Item No.

241. Replace on six transformers.

R. One 2 inch gate valve for the water inlet on heat exchanger number 2. SMIT Item No.

242. Replace on six transformers.

S. One 2 inch gate valve for the water outlet on heat exchanger number 1. SMIT Item No. 251. Replace on six transformers.

T. One 2 inch gate valve for the water outlet on heat exchanger number 2. SMIT Item No. 252. Replace on six transformers.

U. All valves shall be replaced with new valves made of the same material and shall be mounted in a configuration that would not impede the operation or maintenance of a device in the same area.

V. All valves shall be painted the same color as the exterior finish of the transformer.

W. Contractor to submit data sheets for all valves listed above.

2.8 Oil Pumps and Motors

A. Oil pump motors are 460 Volt AC, 60 Hz and shall be replaced with the same voltage and frequency motors and the same horsepower. The existing pump motors are rated 1.8kW and draw 2.9 amps at 460 volts AC. The existing oil pumps have 2 ½ inch connections at the inlet and outlet. They are manufactured by Renzmann & Grunewald type: 25/160/65 UD90.

B. New oil pumps will have 2 ½ inch connections identical to the existing pumps.

C. Contractor to install new motor starters for the oil pump motors. The new starters shall come equipped with the necessary contact and overloads to operate with the existing equipment on the transformer and equipment in the control cabinet. Any additional modifications necessary to operate new pump motors shall be performed by the contractor.

D. Contractor to supply data sheets on oil pumps and motors for approval prior to arrival to job site.

E. Contractor to replace oil pumps and motors on six transformers.

2.9 Heat Exchangers

A. Heat exchangers are manufactured by Bloksma, type N220-2Z-L=1300

B. The heat exchanger shall have a capacity of 136kW or greater.

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C. Heat exchangers shall be double tube with the outer side made of deoxidized high phosphorous copper, not tinned according to ASTM B111 Alloy 122.

D. The inner side of the tube shall be 90-10 copper-nickel according to ASTM B111 Alloy 706.

E. Each heat exchanger shall have 26 tubes.

F. Oil connections shall be 2-1/2”.

G. Water connections shall be 2 inch.

H. Total width of new heat exchanger shall not exceed 68 inches.

I. New heat exchangers shall mount identically to existing heat exchangers and shall be made to match newly installed oil and water valves listed in items F and G under section 2.7.

Contractor shall supply any adapters and piping necessary to mate the new heat exchangers with the new valves.

J. New heat exchangers shall be provided with detection to indicate leaking tubes.

K. The shell and baffles of the new heat exchangers shall be steel.

L. The outside of the heat exchangers shall be painted ANSI 70 light gray and intended for outdoor use.

M. The transformer shall be able to carry a load of 70% with one cooler out of service.

N. The gate valves at the water inlet and outlet of each heat exchanger shall be replaced with 2 inch gate valves made of the same material. The gaskets for these valves shall be replaced with the same style as already installed. The valve operator shall be located where it can be accessed without obstruction.

O. The 2 ½ inch gate valves on the inlet and outlet side of the heat exchangers for the oil inlet and outlet shall be replaced with gate valves made of the same material and the size of the heat exchanger inlet and outlet ports. Contractor shall supply any necessary piping, fittings and adapters to make a complete installation. A complete installation means the heat exchangers are ready for use and are free from both oil and water leaks once the work is finished. The valve operator shall be located where it can be accessed without obstruction.

P. Contractor to submit data sheets on supplied heat exchangers for approval prior to arriving at job site.

Q. Replace heat exchangers on six transformers. Total quantity of heat exchangers supplied and installed will be twelve. All heat exchangers will be manufactured from the same company.

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2.10 Conservator

2.10.1 Air System

A. Conservator Bladder - Contractor shall install a new bladder inside the conservator tank. Information on the conservator bladder is shown on SMIT drawing 210-17104. The existing bladder is made by PRONAL. The bladder is nitrile.