48 19 26.00 26 R0004.pdf

CJD Excitation Units 1 – 16 Replacement 21050 Bridgeport, WA W912DW24R0001

SECTION TABLE OF CONTENTS

DIVISION 48 - ELECTRICAL POWER GENERATION

SECTION 48 19 26.00 26

DIGITAL EXCITERS

PART 1 GENERAL

1.1 GENERAL INFORMATION

1.1.1 Scope of Work

1.1.2 Description of Generators

1.1.3 Description of Existing Excitation System

1.1.4 Generator Characteristic Data

1.1.5 Warranty

1.2 REFERENCES

1.3 SUBMITTALS

1.4 GOVERNMENT EQUIPMENT INTERFACE

1.4.1 DC Voltage Source for Controls

1.4.2 AC Voltage Source for Lighting and Receptacles

1.4.3 Source for Field Flashing

1.4.4 Potential and Current Transformers

1.4.5 Switchboard Contacts

1.4.6 Data Systems

PART 2 PRODUCTS

2.1 GENERAL

2.2 MATERIALS

2.3 CONNECTION TO MEDIUM VOLTAGE SUPPLY

2.3.1 General

2.3.2 Construction

2.3.3 Current Limiting Fuses

2.4 POWER POTENTIAL TRANSFORMERS (PPTs)

2.4.1 Standard Requirements

2.4.2 Enclosure

2.4.3 Transformer Mounting

2.4.4 Temperature Monitoring

2.4.5 AC Conductors Between PPT and Rectifier Supply Breaker

2.5 EXCITATION SYSTEM REQUIREMENTS

2.5.1 General

2.5.1.1 System Characteristics

2.5.1.2 Equipment to be Included

2.5.1.3 Auxiliary Equipment to be Included

2.5.1.4 Adaptation to Plant

2.5.1.5 Minimum Requirements From Standards

2.5.1.6 Digital Control Systems

2.5.2 Bus

2.5.3 Grounding

2.5.4 Wiring

2.5.5 Molded Case Circuit Breakers

2.5.5.1 General

2.5.5.2 Trip Units

2.5.5.3 120 Vac Circuits

2.5.5.4 125 Vdc Circuits

2.5.6 Auxiliary and Interposing Relays

2.5.7 Excitation System Cubicles

SECTION 48 19 26.00 26 Page 1

R0004

2.5.7.1 General

2.5.7.2 Dimensions

2.5.7.3 Cubicle Construction

2.5.7.4 Louvers and Latches

2.5.7.5 Mounting

2.5.7.6 Painting

2.5.8 Rectifier Supply Breaker

2.5.9 Rectifier Assemblies

2.5.9.1 General

2.5.9.2 Rectifier Assembly Cooling

2.5.10 Field Discharge and Surge Suppression

2.5.11 Surge Withstand and Protection Against Stray Currents

2.5.12 Radio Frequency Interference

2.5.13 Overspeed Protection

2.5.14 Redundant Power Supplies

2.5.15 Diagnostics

2.5.16 Test Connections

2.5.17 Convenience Receptacles, Light Fixtures, and Switches

2.5.18 Reversible Bus Link

2.5.19 Exciter Nameplate

2.6 EXCITATION SYSTEM CONTROLS

2.6.1 General

2.6.2 Automatic Control

2.6.3 Automatic Transfer to Alternate Regulator Settings

2.6.4 Manual Control

2.6.5 Local and Remote Modes

2.6.6 Control Transfer Requirements

2.6.6.1 Automatic/Manual Regulator Transfer

2.6.6.2 Regulation Mode Automatic Fail Over Control

2.6.6.3 Channel Transfer

2.6.7 Reactive Compensation

2.6.8 Line Drop Compensation

2.6.9 Overexcitation Limiter (OEL)

2.6.10 Underexcitation Limiter (UEL)

2.6.11 Volts Per Hertz Limiter (V/Hz)

2.6.12 Power System Stabilizer (PSS)

2.6.12.1 General

2.6.12.2 Configuration

2.6.12.3 Input Signals

2.6.12.4 Settings

2.6.12.5 Test and Status Monitoring Features

2.6.13 Excitation System Models

2.7 EXCITER COMMUNICATION

2.7.1 Documentation

2.7.2 Software

2.7.3 Human-Machine Interface (HMI)

2.7.4 Fault Display

2.7.5 Trouble Alarm Relay

2.7.6 Exciter Internal Trip Alarm Relay

2.7.7 Hard-Wired Controls, Metering, and Annunciation

2.7.8 Managed Switches

2.7.9 External Communication Ports

2.7.10 External Communication Protocols

2.8 INTEGRATED PROTECTION AND METERING

2.8.1 Digital Multifunction Relay

2.8.2 Field Ground Protection

2.8.3 Sequence of Events Recorder (SER)

2.8.4 Transient Recorder

2.8.5 Emergency Shutdown

SECTION 48 19 26.00 26 Page 2

2.9 CONNECTION TO GENERATOR FIELD

2.9.1 General

2.9.2 Routing

2.9.3 Construction

2.10 COLLECTOR RING ASSEMBLY MATERIALS

2.10.1 Collector Ring Assembly Inspection

2.10.2 Collector Ring Brushes and Springs

2.10.3 Collector Ring Replacement (optional)

2.11 OTHER EQUIPMENT

2.11.1 Shaft Grounding

2.12 DRAWINGS

2.12.1 Design Drawings

2.12.1.1 Schematic Diagrams

2.12.1.2 Outline Drawings

2.12.1.3 Arrangement Drawings

2.12.2 Shop Drawings

2.12.2.1 Internal Wiring Diagrams

2.12.2.2 Software Logic Drawings

2.12.2.3 Software Parameter List

2.12.2.4 Interface Wiring Diagrams

2.12.3 As-Built Drawings

2.13 SPECIAL TOOLS

2.14 SPARE PARTS

2.15 OPERATION AND MAINTENANCE MANUALS

PART 3 EXECUTION

3.1 ARRANGEMENT

3.2 FACTORY WORK

3.2.1 FACTORY ASSEMBLY

3.2.2 FACTORY TESTS

3.2.2.1 General

3.2.2.2 Excitation Tests

3.2.2.2.1 Routine Tests

3.2.2.2.2 Special Tests

3.2.2.3 Power Potential Transformer Tests

3.2.2.3.1 Routine Tests

3.2.2.3.2 Special Tests

3.3 FIELD WORK

3.3.1 Field Supervisor

3.3.2 Services of Commissioning Engineer

3.3.2.1 General

3.3.2.2 Duties

3.3.3 Existing System Removal

3.3.3.1 General

3.3.3.2 Equipment To Be Removed

3.3.3.3 Cable and Conduit

3.3.3.4 Powerhouse Floor

3.3.3.5 Instrument Panels

3.3.4 Equipment Installation

3.3.4.1 General

3.3.4.2 Equipment To Be Installed

3.3.4.3 Control Board Modifications

3.3.5 Brush Replacement

3.3.6 Collector Ring Refurbishment - Surface Finish

3.3.7 Collector Ring Replacement (optional)

3.3.8 Commissioning

3.3.8.1 General

3.3.8.2 Scheduling

SECTION 48 19 26.00 26 Page 3

3.3.8.3 Operational Checks and Tests

3.3.8.4 Special Tests

3.3.8.5 Efficiency Test

3.4 CONTRACTOR-FURNISHED TRAINING

3.4.1 General

3.4.2 Operator Training

3.4.3 Technician Training

ATTACHMENTS:

as-tested Generator Open Circuit Saturation Curve

Generator Capability Curve

-- End of Section Table of Contents --

SECTION 48 19 26.00 26 Page 4

SECTION 48 19 26.00 26

DIGITAL EXCITERS

PART 1 GENERAL

1.1 GENERAL INFORMATION

1.1.1 Scope of Work

This section covers the work necessary to design; to prepare drawings, data, and installation instructions; to manufacture; to shop test; to prepare and load for shipment; to deliver free on board destination; and to install, to field test, commission, and make completely operational 16 complete digital static excitation system s at the Chief Joseph Powerhouse.

Additional work items include:

a. Remove old excitation system and repair flooring

b. Install cable and conduit for AC and buswork DC connections as specified.

c. Install additional cables and conduit as required for the new excitation systems, including wiring for control and indications

d. Modify control board

e. Install new field ground relay in exciter cabinet.

f. Replace brushes and brush holder springs; retain brush holders.

g. Replace shaft grounding brush.

h. Refurbish (resurface) collector rings and the existing spare collector ring set.

1.1.2 Description of Generators

Generator Unit s 1-16 were manufactured by Westinghouse and commissioned in the 1950s. The three-phase, 60 Hz, salient pole, synchronous hydro-generator s have the following characteristics and ratings, as defined by the nameplate information

Manufacturer Westinghouse (Rewound by Westinghouse in 1987) Year of Commissioning 1950s Rating (kVA) 92,920 Power Factor 0.95 Rated Stator Voltage (V) 13.8 Speed (rpm) 100 Field Resistance 0.38 ohms at 75°C

1.1.3 Description of Existing Excitation System

The existing static-analog excitation system s are manufactured by General Electric. They were installed in the 1980s and include PPT, buswork, and cables. Nameplate information for the existing exciter s is the following.

Rated Excitation Voltage (V) 550 Rated Excitation Current (A) 825 Power Potential Transformer (PPT) Ratio 13,800/550 PPT Rating (kVA) 750

SECTION 48 19 26.00 26 Page 5

1.1.4 Generator Characteristic Data

Copies of the as-tested Generator Open Circuit Saturation Curve and Generator Capability Curve are included in these specifications at the end of this section.

Field Current at Rated load, rated Power Factor: 825 A Synchronous Reactance(p.u): 1.245 (unsaturated) Direct-axis transient open-circuit time constant: 8 sec

1.1.5 Warranty

The complete installed excitation system s shall have an extended warranty period of five (5) years after the successful completion of tests and acceptance. Any component failing to perform its function as specified and documented shall be repaired or replaced by the Contractor at no additional cost to the Government within the five (5) year period. Submit for approval the Exciter Warranty Details, to include duration of warranty coverage and items and labor covered by the warranty.

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.

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

ANSI C39.1 (1981; R 1992) Requirements for Electrical Analog Indicating Instruments

ASTM INTERNATIONAL (ASTM)

ASTM B187 (2020) Seamless Copper Bus Bars, Rod, and Shapes

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

IEEE C37.20.1 (2015) Standard for Metal-Enclosed Low-Voltage Power Circuit-Breaker Switchgear

IEEE C37.90 (2005; R 2011) Standard for Relays and Relay Systems Associated With Electric Power Apparatus

IEEE C37.90.1 (2020) Standard for Surge Withstand Capability (SWC) Tests for Relays and Relay Systems Associated with Electric Power Apparatus

IEEE C37.90.2 (2004)IEEE Standard for Withstand Capability of Relay Systems to Radiated Electromagnetic Interference from Transceivers

IEEE C57.12.01 (2015) General Requirements for Dry-Type Distribution and Power Transformers Including Those with Solid-Cast and/or

SECTION 48 19 26.00 26 Page 6

Resin-Encapsulated Windings

IEEE C57.12.91 (2011) Standard Test Code for Dry-Type Distribution and Power Transformers

IEEE C57.110 (2018) Recommended Practice for Establishing Liquid-Filled and Dry-Type Power and Distribution Transformer Capability When Supplying Nonsinusoidal Load Currents

IEEE 48 (2020) Standard for Test Procedures and Requirements for Alternating-Current Cable Terminations Used on Shielded Cables Having Laminated Insulation Rated 2.5 kV through 765 kV or Extruded Insulation Rated 2.5 kV through 500 kV

IEEE 421.1 (2007) Definitions for Excitation Systems for Synchronous Machines

IEEE 421.2 (2014) Guide for Identification, Testing, and Evaluation of the Dynamic Performance of Excitation Control Systems

IEEE 421.3 (2016) High-Potential Test Requirements for Excitation Systems for Synchronous Machines.

IEEE 421.5 (2016) IEEE Recommended Practices for Excitation System Models for Power System Stability Studies

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

NEMA WC 57 (2014) Standard for Control, Thermocouple Extension, and Instrumentation Cables

NEMA WD 1 (1999; R 2015) General Color Requirements for Wiring Devices

NEMA WD 6 (2016) Wiring Devices Dimensions Specifications

INTERNATIONAL ELECTRICAL TESTING ASSOCIATION (NETA)

NETA MTS (2019) Standard for Maintenance Testing Specifications for Electrical Power Equipment and Systems

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

NFPA 70 (2020) National Electrical Code

UNDERWRITERS LABORATORIES (UL)

UL 20 (2018) Standard for Safety General-Use Snap Switches

SECTION 48 19 26.00 26 Page 7

UL 489 (2019) Molded-Case Circuit Breakers, Molded-Case Switches, and Circuit-Breaker Enclosures

UL 498 (2021) Attachment Plugs and Receptacles

UL 1054 (2003, R 2005, R 2013) Special Use Switches

UL 1066 (2017) Low-Voltage AC and DC Power Circuit Breakers Used in Enclosures

U.S. NATIONAL ARCHIVES AND RECORDS ADMINISTRATION (NARA)

29 CFR 1910 (2017) Occupational Safety and Health Standards

1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation. The following shall be submitted in accordance with SECTION 01 33 00 SUBMITTAL

PROCEDURES:

SD-01 Preconstruction Submittals

Within 90 calendar days after receipt of written notice to proceed:

Excitation System Component Rating Details; G

Factory Routine Test Procedure; G

Factory Special Test Procedure; G

Power Potential Transformer Test Procedures; G

Manufacturer's Relay Descriptive Literature

Within 120 calendar days after receipt of written notice to proceed:

Excitation Equipment Removal Procedure; G

Brush Replacement Procedure; G

Collector Ring Refurbishment Procedure; G

(Optional) Collector Ring Replacement Procedure; G

Installation Procedure; G

Commissioning Procedure; G

SD-02 Shop Drawings

Within 60 calendar days after receipt of written notice to proceed:

Outline Drawings; G

Schematic Diagrams; G

SECTION 48 19 26.00 26 Page 8

Software Logic Drawings

Within 90 calendar days after written notice to proceed:

Arrangement Drawings; G

Shaft Grounding Assembly and Brush Drawing; G

Exciter Nameplate; G

Within 120 calendar days after receipt of written notice to proceed:

Internal Wiring Diagrams; G

Interface Wiring Diagrams; G

Within 150 calendar days after receipt of written notice to proceed:

Brushes And Brush Springs Drawings; G

(Optional) Replacement Collector Ring Drawing; G

SD-03 Product Data

Within 60 calendar days after receipt of written notice to proceed:

Excitation Equipment Models

Fuse Ratings; G

Rectifier Supply Breaker; G

Within 150 calendar days after receipt of written notice to proceed:

Contractor-Furnished Training Instructor

Exciter Warranty Details; G

Brush Product Data; G

Reversible Bus Link; G

Exciter Test Laptop Software; G

SD-05 Design Data

Within 60 calendar days after receipt of written notice to proceed:

Exciter Communications Documentation

Software Parameter List

Within 90 calendar days after written notice to proceed:

Parts List; G

Spare Parts List; G

Within 150 calendar days after written notice to proceed:

SECTION 48 19 26.00 26 Page 9

Brush Current Density Calculations; G

SD-06 Test Reports

Within 10 calendar days after completion of the test or inspection (unless otherwise noted):

Factory Routine Test Report; G

Factory Special Test Report; G

Power Potential Transformer Test Report; G

Collector Ring Data; G

Commissioning Report; G

Collector Ring Assembly Inspection Report; G

SD-07 Certificates

Within 120 calendar days after receipt of written notice to proceed:

Commissioning Engineer's Qualifications; G

SD-08 Manufacturer's Instructions

Within 150 calendar days after receipt of written notice to proceed:

Contractor Furnished Training Details; G

SD-10 Operation and Maintenance Data

Operation and Maintenance Manuals; G See SECTION 01 78 23 OPERATIONS AND MAINTENANCE DATA.

1.4 GOVERNMENT EQUIPMENT INTERFACE

1.4.1 DC Voltage Source for Controls

DC control power is supplied from a properly protected, ungrounded, nominal 125 Vdc source, which has a range of 105 Vdc to 140 Vdc, to be used for inputs, status outputs, and annunciation.

1.4.2 AC Voltage Source for Lighting and Receptacles

Non-preferred 120 Vac single-phase power is available to supply convenience receptacles, light fixtures, and heaters.

1.4.3 Source for Field Flashing

Nominal 125 Vdc power is supplied for field flashing, not to exceed 70 A for 10 seconds.

1.4.4 Potential and Current Transformers

Three potential transformers (PTs), rated 14,400/120 V, are installed for each unit in a wye-wye configuration. One current transformer (CT)

SECTION 48 19 26.00 26 Page 10 dedicated to the present voltage regulator rated 4000:5 currently installed at a 798 Gallery.

1.4.5 Switchboard Contacts

Contacts from generator lockout relays as well as other control, protective, and relaying devices are located on the existing switchboards.

Contacts will be dry. Voltages for contacts shall be provided by the excitation system, and shall be selected such that the voltage drop over the conductor length does not impair functionality.

1.4.6 Data Systems

Existing Powerhouse data systems utilize Modbus communication protocols.

PART 2 PRODUCTS

2.1 GENERAL

Provide 16 excitation system s consisting of a full inverting potential source rectifier exciter including the rectifier assembly and the power potential transformer (PPT). Provide redundant controllers as specified herein. The excitation system s shall be microprocessor (digital) controlled and capable of continuous operation with powerhouse environmental conditions of 40°C and 95 percent relative humidity (non-condensing). The equipment provided under these specifications shall be of a type having an established reputation of two years or more of satisfactory and reliable service, designed for field excitation and voltage regulation of hydroelectric generators. The operation and performance of the equipment furnished shall be guaranteed by the manufacturer to meet the requirements of these specifications. The excitation systems for all units shall be, insofar as possible, identical in design and construction. The requirements of this specification for the design, drawings, manufacture, factory test, and delivery of excitation systems apply to all 16 units provided unless otherwise specified herein.

2.2 MATERIALS

All materials shall conform to the applicable requirements of these specifications. The classification and grade of materials incorporated in the work shall be in accordance with the specifications designated herein.

Substitution of materials from those specified shall not be made except on specific prior written approval. Any materials required in the work not covered by specifications shall be submitted for approval for the purpose intended. The use of asbestos or polychlorinated biphenyls (PCBs) shall not be permitted.

2.3 CONNECTION TO MEDIUM VOLTAGE SUPPLY

2.3.1 General

Connect to the 13.8 kV terminal voltage supply in a manner as specified in the drawings to provide medium voltage power supply to the PPT.

2.3.2 Construction

The 13.8 kV terminal voltage bus tap method shall meet the requirements of SECTION 26 05 13.00 26 MEDIUM-VOLTAGE CABLE. The AC conductors from the generator bus tap to the current limiting fuses (CLFs) and from the CLFs

SECTION 48 19 26.00 26 Page 11 to the PPT shall be properly sized and rated medium voltage cable. Cable and terminations shall meet the requirements of SECTION 26 05 13.00 26 MEDIUM-VOLTAGE CABLE and IEEE 48 .

2.3.3 Current Limiting Fuses

Three new current limiting fuses (CLFs) shall be provided at the tapping of generator and shall fit in the existing holders Three new current limiting fuses (CLFs) shall be provided, to be installed in the existing compartment at the top of the generator air housing for each unit. The existing fuse holders may be reused, if the new fuses are compatible with the existing holders. The Contractor is responsible for replacing the fuse holders if required to suit the new fuses provided . Submit Fuse Ratings for approval. The fault current available at the generator terminals is 65 kA, symmetrical.

2.4 POWER POTENTIAL TRANSFORMERS (PPT s)

2.4.1 Standard Requirements

One PPT shall be provided for each unit and be of the three-phase, 60 Hz, self-cooled, ventilated, Vacuum Pressure Impregnated (VPI) dry type, conforming to the applicable requirements of IEEE C57.12.01 , Basic Insulation Level (BIL) on the high voltage winding of 95 kV. The winding material shall be copper. The PPT s furnished shall also conform to the recommended practice of IEEE C57.110 and shall be designed specifically for supplying a thyristor-controlled rectifier load. The PPT s shall be of sufficient rating to deliver the required input power to the exciters when operating under the required conditions as defined in paragraph 2.5.1.1, with an average winding temperature rise by resistance not to exceed 150°C. Hottest spot winding temperature rise shall not exceed 110°C. For each unit, t hree suitable relaying accuracy current transformers (CTs) shall be installed on the PPT primary for use with the overcurrent relay.

Use ring type terminals for CT wiring. The PPT s shall be designed for floor mounting and included ground ball studs, with secondary connection to the excitation equipment.

2.4.2 Enclosure

The PPT s shall be enclosed in a ventilated enclosure with protection against ingress of solid foreign objects and water due to dripping and light splashing. Ventilation openings shall be limited to screened openings at the top and/or bottom of the sides of the enclosure as necessary to meet temperature requirements. The enclosure shall meet the seismic requirements of SECTION 13 48 00.00 26, SEISMIC RESTRAINT FOR MECHANICAL AND ELECTRICAL EQUIPMENT. The cubicle s shall be of the totally enclosed, freestanding, dead-front type built on a suitable framework of structural steel or by an equivalent approved method. Provide grounding ball studs on the primary PPT conductors to allow for hot-stick application of grounding cables. In the same enclosure, provide three grounding ball studs on the ground bus as well.

2.4.3 Transformer Mounting

The PPT s shall be designed for floor mounting, with secondary connection to the excitation equipment as described in paragraph 2.4.6. Floor mounts with appurtenances shall be furnished for the PPT, meeting the requirements of SECTION 13 48 00.00 26, SEISMIC RESTRAINT FOR MECHANICAL

AND ELECTRICAL EQUIPMENT.

SECTION 48 19 26.00 26 Page 12

2.4.4 Temperature Monitoring

The PPT temperature shall be sensed by three-wire RTDs and shall be furnished with a temperature indicator mounted on the PPT cubicle in a manner that enables reading of the indicator from the location indicated on contract drawings. The temperature indicator shall display the phase A, phase B, phase C, and average temperature, shall be powered by 125 Vdc, and shall be equipped with a minimum of two normally open contacts to provide alarm and trip functions. Remote temperature indication from the temperature monitoring device to the excitation system HMI shall be provided in addition to the local indication at the PPT. Provide open and short circuited RTD sensor detection. Alarm and trip settings shall be user adjustable. Temperature sensor leads shall meet applicable requirements of NEMA WC 57. The alarm and trip contacts shall be wired to terminal blocks in the excitation cabinets.

2.4.5 AC Conductors Between PPT and Rectifier Supply Breaker

Any ac conductors routed from the PPT to the rectifier supply circuit breaker and external to the excitation system cubicles shall be of properly sized and rated cable. Cable shall meet the requirements of

SECTION 26 05 19.00 26, INSULATED WIRE AND CABLE.

2.5 EXCITATION SYSTEM REQUIREMENTS

2.5.1 General

The exciter s shall be rated for continuous operation at, or above, 1,000 Adc. The excitation system s shall meet the requirements for a High Initial Response Excitation System as per IEEE 421.1 . Provide Excitation System Component Rating Details, to include ratings of the following components at a minimum:

(a) AC conductors between PPT and Rectifier Supply Breaker (continuous current)

(b) Rectifier Supply Breaker (continuous current)

(c) Internal AC and DC bus (continuous current)

(d) Rectifier Assemblies (continuous current, maximum supply voltage)

(e) Field suppression system (short term current, energy dissipation)

2.5.1.1 System Characteristics

The excitation system s shall be capable of the following performance:

Positive No-Load Ceiling Voltage +470 Vdc

Source Voltage 70% rated

Negative Field Forcing Full negative field forcing, with allowance for thyristor firing margins as approved

Excitation System Rated Current 1,000 Adc Continuous, Minimum

SECTION 48 19 26.00 26 Page 13

Positive No-Load Ceiling Voltage +470 Vdc

Excitation System Ceiling Current Requirement

1,500 Adc for 30 seconds

The excitation system s shall be capable of achieving the positive no-load ceiling voltage at the specified source voltage.

2.5.1.2 Equipment to be Included

The excitation system s shall be in accordance with this specification and the approved outline drawings, schematic diagrams, wiring diagrams, and other drawings as required, and shall be complete and include but not be limited to the following: excitation cubicles, ac supply breaker, input/output (I/O) cards, communication cards, redundant regulator controllers, rectifier assemblies, dc conductors to the generator housing, all auxiliaries necessary for satisfactory operation of the regulator such as control and potential transformers, potentiometers, thyristors, resistors, rheostats, reactors, shunts, contactors and relays, and spare parts. The excitation system s shall be ready for operation upon completion of installation, wiring and testing.

A Parts List shall list all parts to be included in each excitation system, with each part numbered and cross-referenced to the drawings. Each part shall be identified by name, manufacturer, and rating (ohms, farads, etc.), as appropriate.

2.5.1.3 Auxiliary Equipment to be Included

All additional external items required for proper operation and control shall be provided, and shall meet the applicable requirements of ANSI C39.1 .

All additional external items required for proper operation and control such as control switches, transfer switches, and indicating instruments to be mounted at the generator (unit) switchboard and in the powerhouse control room shall be provided. The excitation system design shall include the determination of required external items in addition to those devices which are specifically called out herein. Any supplied switchboard devices shall be compatible, in function and appearance, with existing equipment.

2.5.1.4 Adaptation to Plant

The excitation equipment and all assemblies for interconnection of the exciter with existing equipment and facilities shall be custom fabricated for the site such that a minimum of on-site cutting and fitting is required. The equipment and assemblies shall include adaptive features to accommodate minor dimensional variations in existing equipment and structures.

2.5.1.5 Minimum Requirements From Standards

All equipment and materials shall be furnished and installed in accordance with NFPA 70 and the requirements of 29 CFR 1910 . Omission of details on the contract drawings, or in the specifications, shall not be construed as permitting deviations from NFPA 70 . Rating, tests, and characteristics shall be in accordance with IEEE 421.1 , IEEE 421.2 , and IEEE 421.3 , each as they apply, unless otherwise specified herein.

SECTION 48 19 26.00 26 Page 14

2.5.1.6 Digital Control Systems

The Contractor shall have responsibility for the design, manufacture, and testing of all digital control systems that are part of the supplied excitation equipment. Memory use for the operation program, configuration, alarms and setpoints shall be non-volatile, without the need for changing batteries, or for other maintenance, over the life of the excitation system. Programming language access for maintenance, troubleshooting, special testing and parameter adjustment, and operation purposes shall be in the English language.

2.5.2 Bus

All internal buswork shall be sized and rated appropriately for anticipated current requirements and ratings, and shall meet the requirements of ASTM B187. All connections shall be silver plated and torque marked on final assembly. Provide copper ground ball studs on the positive and negative buses of the excitation systems such that they are accessible by hot stick clamps.

2.5.3 Grounding

Each excitation system cubicle assembly shall be provided with a continuous interior copper ground bus to which the housing, framework, cable and bus supports, and non-current-carrying metallic parts of all equipment shall be grounded insofar as practicable. Grounding shall conform to paragraph 7.1.2 of IEEE C37.20.1 . Additionally, the ground bus bar shall be copper and shall not be less than 1 inch by 1/4 inch in size.

Ground connections shall be made by approved clamp-type fittings; soldered connections shall not be used. Splices in ground buses between shipping sections shall be provided with splice plates and hardware for bolted connections. Bus bar splice contact surfaces shall be tinned or silver-plated. Jumper cables or copper bars shall be provided for connecting the ground bars at shipping splits. Provide two (2) permanent grounding ball studs on the ground bus internal to the exciter in an area accessible by hot stick clamps. The ground bus grounding ball studs shall be located in the same cubicles as those installed on the positive and negative busses of the excitation system. Multigrip clamp-type cable terminals for No. 2/0 AWG cables shall be provided for connection to the station grounding system for each ground bus. Control cable shields shall be grounded only once.

2.5.4 Wiring

All enclosures and devices shall be completely wired to designated terminal blocks for connection to external devices. The Contractor's standard cables and methods of cable terminations may be used between standard modules within the cubicles. Each wire shall be uniquely identified by wire labels. Wiring, where not installed in channels or ducts, shall be formed into compact wire bundles bound together and properly supported. Hinge wire shall be used between stationary panels and swinging doors and shall be formed in wire loops, which will provide rotation around the longitudinal axis of the conductors. Hinge wire shall be Class K stranding. Any wiring extending beyond the equipment cubicles shall be terminated at 600 V terminal blocks meeting the requirements described in SECTION 26 05 00.00 26 with the exception of excitation system power leads such as generator field leads, shunt leads, etc. Leave spare terminal block spaces available on these terminal blocks for potential future wiring. Special attention shall be given to terminal

SECTION 48 19 26.00 26 Page 15 wiring arrangements on the terminal blocks to permit individual conductors of each external cable to be terminated on adjacent terminal points. The wire (terminal point) designations used on the Contractor's wiring diagrams may be according to the Contractor's standard practice; however, additional wire and cable designations for identification of external circuits shall be as shown on the approved drawings.

2.5.5 Molded Case Circuit Breakers

2.5.5.1 General

Molded case circuit breakers shall conform to the applicable requirements of UL 489 , shall be fully rated, and shall have voltage ratings and interrupting ratings hereinafter stated. The circuit breakers shall be manually operated and shall have trip-free operating mechanisms of the quick-make, quick-break type. All poles of each breaker shall be operated simultaneously by means of a common handle, and shall be enclosed in a common molded plastic case. The operating handles shall clearly indicate whether the breakers are in "On," "Off," or "Tripped" position. All double-pole, 125 Vdc molded case circuit breakers for the control and field-flashing circuits shall conform to the applicable requirements of UL 489 and shall be of the heavy duty type. Circuit breakers shall be equipped with a lockout device, when normally available, not of any special manufacture.

2.5.5.2 Trip Units

The circuit breakers shall be of the automatic type provided with combination thermal and instantaneous magnetic trip units. Instantaneous magnetic trip units shall be set at approximately 10 times the continuous ratings of the circuit breakers.

2.5.5.3 120 Vac Circuits

Circuit breakers for 120 Vac circuits shall be rated not less than 120/240 or Vac, and shall be a UL listed minimum interrupting capacity of 14,000 symmetrical amperes at 600 Vac.

2.5.5.4 125 Vdc Circuits

Circuit breakers for 125 Vdc circuits shall be two-pole, rated 125/250 Vdc or 125 Vdc, and shall be a UL listed minimum interrupting capacity of 42,000 symmetrical amperes at 250 Vdc.

2.5.6 Auxiliary and Interposing Relays

Auxiliary and interposing relays shall be of the self-reset type and shall be provided with convertible contacts. Relay coils and contacts shall be suitable for continuous operation in 125 Vdc or 120 Vac circuits as required. Contacts shall have a 10 A continuous current rating. The single-contact inductive load interrupting capacity shall not be less than

1.0 A for 125 Vdc or 6 A for 120 Vac. Relays used in 125 Vdc circuits shall operate reliably between 90 and 140 Vdc. Relay coils used in 125 Vdc circuits shall be capable of handling 140 Vdc continuously. All inductive devices, such as relays and solenoids, shall be provided with suppression devices to limit surge voltages, which may be generated when the coil circuits are interrupted. The relays shall have visual indication of their status.

SECTION 48 19 26.00 26 Page 16

2.5.7 Excitation System Cubicles

2.5.7.1 General

Excitation system cubicles shall be ventilated with protection against ingress of solid foreign objects and water due to dripping and light splashing. Ventilation openings shall be limited to screened and filtered openings at the top and/or bottom of the sides of the enclosure as necessary to meet temperature requirements. Heat producing components of the excitation system shall be located such that they do not cause damage to, or adversely affect, surrounding components of the system. Surface temperature on the sides of the excitation system cubicles shall not exceed 50°C in any location.

2.5.7.2 Dimensions

Footprints for the excitation system cubicles shall not exceed the existing excitation system footprint. The Contractor shall investigate the site to ensure that the cubicles provided will fit in the specified area without impinging on the operation of existing equipment or the new excitation equipment. Cubicle design shall be modified as required to conform to site conditions.

2.5.7.3 Cubicle Construction

All cubicles shall meet the seismic requirements of SECTION 13 48 00.00 26, SEISMIC RESTRAINT FOR MECHANICAL AND ELECTRICAL EQUIPMENT. The cubicles shall be of the totally enclosed, freestanding, dead-front type built on a suitable framework of structural steel or by an equivalent approved method. Each cubicle shall consist of rigid, self-supporting, enclosed panels with full-length doors or pullout drawers arranged to provide easy access to the equipment. The enclosures shall be made of selected smooth sheet steel panels, suitably supported. Doors and panels used to support instruments and other devices and barriers between compartments shall not be thinner than No. 12 gauge steel. Doors shall be mounted with continuous hidden hinges or other approved hinges. Exposed panels on the front and ends of the enclosures shall be bent angle or channel edges with all corner seams welded and ground smooth, or shall be the manufacturer's equivalent construction as approved by the Contracting Officer's Representative (COR). The front outside surfaces shall not be drilled or welded for the purpose of attaching wires or mounting devices if such holes or fastenings will be visible from the front. With the exception of nameplates, self-tapping sheet metal screws will not be allowed.

2.5.7.4 Louvers and Latches

Punched louvers necessary for adequate ventilation shall be provided where required. Louvers shall be designed or screened to prevent the entrance of insects and rodents. All doors shall be equipped with a handle, a minimum three-point latch, and flush lock. Six control keys shall be provided for removal of the lock cores.

2.5.7.5 Mounting

Continuous channel steel foundations, complete with bolts and drilled holes for anchoring to the floor, shall be furnished for the complete length front and rear of the cubicle assembly. The anchoring of the channel and seismic mounting of the equipment shall comply with the applicable requirements of SECTION 13 48 00.00 26. Foundation channel

SECTION 48 19 26.00 26 Page 17 construction and drilling shall be as required for mounting the equipment.

The foundation channels shall be designed for flat mounting and maximum channel depth shall be 2-1/2 inches. Mount all enclosures plumb and level.

2.5.7.6 Painting

The interior and exterior steel surfaces of the excitation system equipment enclosures, including the power potential transformer and fuse cabinet enclosures, shall be thoroughly cleaned after fabrication by sandblasting, pickling and rinsing, or by other means. They shall then receive a rust-inhibitive phosphatizing or equivalent treatment prior to painting. Exterior surfaces shall then be primed, filled where necessary, and given not less than two coats of Contractor's standard light gray finish. Interior surfaces shall receive not less than one coat of corrosion-resisting paint in accordance with the manufacturer's standard practice.

2.5.8 Rectifier Supply Breaker

The Contractor shall provide a three-pole, adequately rated, rectifier supply air circuit breaker for the excitation system, conforming to the requirements of UL 1066 . The breaker shall be provided with arc extinguishers, and the operating mechanism shall be trip-free in all positions. It shall be of the drawout type arranged for remote 125 Vdc electrically trip-free operation. The breaker shall have the capability of being locked in the racked out and disconnected position to facilitate Lock Out Tag Out (LOTO). The breaker shall be provided with three type 'a' and three type 'b' auxiliary contacts, meeting the requirements of paragraph 2.5.6. The breaker shall be rated not less than the maximum continuous current of the circuit under the specified operating conditions of the generator, and shall also be capable of interrupting the available fault current under maximum possible short circuit conditions. The contacts shall be of the type which are readily accessible for inspection and replacement. A circuit breaker enclosed in a molded case will not be acceptable. The breaker shall be placed in its mounting cubicle in such a way that it is fully enclosed within the excitation system cubicles, may easily be withdrawn for inspection and testing, and such that the breaker may be manually controlled without opening the excitation cubicle.

2.5.9 Rectifier Assemblies

2.5.9.1 General

Rectifier assemblies shall be of the full inverting type. Thyristors of rectifier assemblies shall have a minimum rating of 350% of the rectifier nameplate RMS voltage rating. Thyristors shall have a peak inverse voltage rating greater than 275% of the PPT nominal secondary voltage.

2.5.9.2 Rectifier Assembly Cooling

Cooling for each rectifier assembly shall be by forced air convection. Fan cooling for each rectifier assembly shall consist of two sets of fans either of which can supply sufficient cooling air to keep the rectifier assembly within the normal operating temperature limits of the assembly components when delivering rated output continuously. A protective scheme shall be provided to automatically throw over to the alternate set of fans upon loss of primary fans. Manual/Auto and lead/lag mode selector functions shall be included for fan operation. Reset functionality shall be provided for returning the lead-selected fan to operation. Fans shall

SECTION 48 19 26.00 26 Page 18 operate automatically upon startup (including black start conditions) without the need for manual reset. An anemometer or vane switch, air pressure switch, fan tachometer, or other approved method shall be provided for monitoring airflow in the rectifier assemblies, and shall provide remote indication to the existing SCADA system. The forced air cooling system shall include air filters. Filters shall be of large cross-sectional area to ensure a low pressure drop and shall be of a type easily replaceable without tools. Inlet air shall not be drawn from near the floor to prevent rapid clogging of the air filters. Filters shall be aluminum, electrostatic, washable, permanent, or reusable. If aluminum filters are furnished, they shall contain layers of expanded aluminum laid at right angles to one another to achieve maximum filtering. The rectifier assembly shall have sufficient self-cooling capacity to allow startup of the generator without the need for external station service power.

2.5.10 Field Discharge and Surge Suppression

Circuitry shall be furnished to protect the generator field and connected excitation system components from overvoltage due to unusual operating conditions. Protective circuitry shall be furnished to provide a path for the field current and to dissipate the stored energy in the field. The circuitry shall incorporate bi-directional thyristors with a field discharge resistor, or similar approved circuitry. Current through the field discharge circuit shall be monitored for unexpected operation of the field discharge system. In the event of unexpected operation, a generator shutdown shall be triggered.

2.5.11 Surge Withstand and Protection Against Stray Currents

The excitation system s shall be designed and tested for surge withstand capability in accordance with IEEE C37.90.1 . The excitation system s shall be adequately protected against stray currents and voltage surges.

2.5.12 Radio Frequency Interference

The excitation system s shall be insensitive in operating condition to radiated high-frequency interference such as that coupled from portable radio transmitters (typically up to 10-watt output in the 138-174 MHz band) operating within 1 meter of the exciter equipment.

2.5.13 Overspeed Protection

The exciter s shall be capable of uninterrupted operation during a full-load rejection and sustain no damage while controlling terminal voltage within the automatic voltage regulator operation range. The exciter s shall also be capable of withstanding sustained generator overspeed, 163 rpm, without damage, however the exciter s may shut down for this condition.

2.5.14 Redundant Power Supplies

Provide redundant internal power supplies capable of independently powering all required internal devices. Each power supply shall be powered from two different sources. In the event of failure of an operating power supply, transfer to the backup power supply shall not result in the loss of operation of the exciter and an alarm indication via the human-machine interface (HMI) shall be given.

SECTION 48 19 26.00 26 Page 19

2.5.15 Diagnostics

Diagnostics and self-tests shall be automatically performed on power-up of the voltage regulator to verify that all excitation system hardware and software is fully operational. After power-up, the digital computer shall continuously verify that it is performing all of its tasks without error.

Both on-line and off-line diagnostics shall be provided as follows:

(a) On-Line Diagnostics. Digital control systems shall include software to continuously monitor hardware and software performance in real time with minimum interference with normal system functions.

(b) Off-Line Diagnostics. The off-line diagnostics shall permit, to the maximum extent possible, the diagnosis and identification of any hardware fault through the HMI and exciter test laptop without requiring additional test equipment. Test points shall be provided to allow the insertion of signals, configurable to numerous locations within the control system. Test points shall also be provided which allow for the output of signals, configurable to any signal within the control system. Provision for a complete operational test of the voltage regulator, without energizing the generator, shall be included. All functional units shall be field repairable to the extent that replacement of a failed subassembly or module shall restore the unit to normal operating condition.

(c) Exciter Test Laptop Software. The Contractor shall provide necessary software for commissioning and troubleshooting the exciter for Chief Joseph's existing maintenance laptops, no later than 30 days prior to the commissioning of the first unit. The government maintenance laptops have the following specs: Model Dell Precision 7510, Operating System Windows 10 Enterprise x64, version 20H2 2021 LTSC , and Memory 16 GB. If the Government's laptop is not suitable to use with the exciter software, the Contractor shall provide a new laptop in factory-sealed packaging, along with installation media for Government installation of proven software for exciter workstation terminal interface meeting the following minimum requirements:

(1) Quad Core 2.30 GHz Processor, 6 MB Cache, 8 GB RAM, Windows 10 Pro Enterprise 2021 LTSC 64 Bit English Operating System, system hardware, including the peripherals, communications, 15.6 inch HD display, 256 GB solid state hard drive, CD or DVD with read/write capability disk drives, and all required cabling.

(2) Digital application software, including the operating system, data base management software, compilers, tools used for commissioning and testing, and other utility programs. If specialized software is required it shall be approved prior to use. Access to the software shall be password protected. Any loss of excitation control power shall not cause loss of the programming or data, to include alarm and event records. Software Logic Drawings shall also be included.

(3) All equipment required for software editing at the job-site, including configuration of protective features and changing of setpoints.

(4) Integration of all Contractor-supplied hardware and software.

SECTION 48 19 26.00 26 Page 20

2.5.16 Test Connections

Provide one isolated Analog Input and three isolated Analog Outputs of -10 to +10 VDC range, for testing purposes. The test input and outputs shall be configurable and scalable internally via software to various parameters.

2.5.17 Convenience Receptacles, Light Fixtures, and Switches

Wiring devices shall conform to NEMA WD 1. Dimensional requirements of wiring devices shall conform to NEMA WD 6. Lighting switches shall conform to the requirements of UL 20 or, if door-activated plunger switches, to UL 1054 . Receptacles shall be of the same quality of construction and materials as similar items conforming to UL 498 . Light fixtures shall be of the light-emitting diode type and shall be provided with suitable guards. A convenience receptacle and light fixture with switch shall be provided in each equipment cubicle. These items shall be hardwired and designed and installed for permanent installation and not cord and plug connected. Location of the receptacles and light switches shall be where access to them can be made without reaching over or under exposed energized conductors.

2.5.18 Reversible Bus Link

Provide and submit drawings for a reversible bus link on the output of the excitation system for the purpose of reversing polarity to the collector rings. The bus link shall be housed within the excitation system cubicles and in a readily accessible location.

2.5.19 Exciter Nameplate

The manufacturer shall supply and attach to each excitation cubicle assembly a nameplate. The nameplate shall be made of laminated sheet plastic or stainless steel approximately 1/8 inch thick and engraved, embossed, or etched to provide white letters on a black background or black letters on a silver background. The nameplate shall be fastened to the panels in proper positions with black finished roundhead screws.

Manufacturer nameplate information shall include the following at a minimum:

(a) Manufacturer's name

(b) Date of manufacture

(c) Serial number

(d) Rated excitation voltage

(e) Positive and negative full-load ceiling voltages

(f) Exciter rated continuous current

(g) Exciter ceiling current and duration

2.6 EXCITATION SYSTEM CONTROLS

2.6.1 General

The digital excitation system s shall be provided with two fully independent and identical control channels, either of which can be selected as the active channel. Each channel's digital voltage regulator shall be capable of both automatic and manual regulation. Each control channel shall be rectifier independent, meaning that each control channel shall be able to operate with either rectifier assembly. The digital voltage regulator shall include a power system stabilizer, overexcitation limiter, underexcitation limiter, volts per hertz limiter, soft start

SECTION 48 19 26.00 26 Page 21 limiter, and protective functions. The regulator shall remain in service upon generator load rejection .

The digital voltage regulator shall be a continuously acting regulator with the following characteristics:

Voltage accuracy (with steady-state load ± 0.2% conditions within operating range of regulator)

Maximum generator voltage change (with ± 0.2% slow changes in ambient temperatures from 15°C to 40°C, after regulator elements have stabilized)

Maximum generator terminal voltage percent 105% of voltage setting (with steady-state conditions, generator open-circuited, generator speed up to 180 percent of nameplate)

2.6.2 Automatic Control

The automatic voltage regulator (ac regulator) shall control generator terminal voltage by continuous comparison of the average three phase voltage of the generator with the reference setpoint. The error voltage shall be amplified and applied to the excitation system in such a manner as to adjust generator voltage to reduce the error. The automatic voltage regulator shall be capable of remote adjustment and have preset voltage adjustment limits as shown on the following table.

Minimum, kV 11.7 Normal SNL, kV 13.8 Maximum, kV 15.2

The automatic voltage regulator control range lower and upper adjustment limits shall be adjustable via software parameter settings. The automatic voltage regulator shall provide outputs capable of interfacing with 125 Vdc remote indicating lights or plant control system inputs for indication that the regulator is at the minimum or maximum level of the control range.

2.6.3 Automatic Transfer to Alternate Regulator Settings

The automatic voltage regulator shall be tuned to operate with separate settings for when the power system stabilizer (PSS) is in service and for when the PSS is off. The voltage regulator shall be capable of storing two sets of parameters and making an automatic, bumpless, on-line transfer from one set to the other when the PSS status changes. The PSS status shall be dependent upon output power level.

2.6.4 Manual Control

The manual regulator mode (dc regulator) shall operate in a similar fashion to the automatic regulator, except that it shall compare generator field current to a reference setpoint, and control excitation to reduce the error between them. When starting in the manual mode, the regulator shall control the field current in order to build machine voltage to approximately 50% and maintain that setpoint awaiting further operator action. The manual regulator mode shall be capable of local-manual and remote adjustment and have the following preset field current adjustment

SECTION 48 19 26.00 26 Page 22 limit levels.

Minimum, A 200 Normal SNL, A 400 Maximum, A 1,000

The manual regulator mode control range lower and upper adjustment limits shall be adjustable via software parameter settings. The manual regulator mode shall provide outputs capable of interfacing with 125 Vdc remote indicating lights or plant control system inputs of indication that the regulator is at the minimum or maximum level of the manual regulator mode control range.

2.6.5…