Amendment_No._0002_to_R17PS00307.pdf

(x)

R17PS00307

x x copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted ; or (c) By separate letter or telegram which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGEMENT TO BE RECEIVED AT

THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER. If by virtue of this amendment you desire to change an offer already submitted , such change may be made by telegram or letter, provided each telegram or letter makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

x

Sacramento CA 95825-1898 2800 Cottage Way, Room E-1815

R20

Division of Acquisition Services Regional Office Mid-Pacific Region Bureau of Reclamation

20-C086307/24/2017000002

13. THIS ITEM ONLY APPLIES TO MODIFICATION OF CONTRACTS/ORDERS. IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.

12. ACCOUNTING AND APPROPRIATION DATA (If required) is not extended.is extended, Items 8 and 15, and returning

Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended , by one of the following methods: (a) By completing

The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offers

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

FACILITY CODE CODE

10B. DATED (SEE ITEM 13)

10A. MODIFICATION OF CONTRACT/ORDER NO.

9B. DATED (SEE ITEM 11)

9A. AMENDMENT OF SOLICITATION NO.

CODE

8. NAME AND ADDRESS OF CONTRACTOR (No., street, county, State and ZIP Code)

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

PAGE OF PAGES

4. REQUISITION/PURCHASE REQ. NO.3. EFFECTIVE DATE2. AMENDMENT/MODIFICATION NO. 5. PROJECT NO. (If applicable)

1. CONTRACT ID CODE

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT

07/18/2017

CHECK ONE A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE CONTRACT

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority) appropriation date, etc.) SET FORTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(b).

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

ORDER NO. IN ITEM 10A.

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

Legacy Doc #: BOR

The Solicitation cited in block 9A above, Shasta and Keswick Powerplants Excitation System

Replacements is hereby amended.

Purpose: The purpose of this amendment is to incorporate the attached Q&A and the attached revised Specification Section 48 19 80.

The date and time for receipt of offers is hereby UNCHANGED and remains August 17, 2017 at

2:00 p.m.

The offeror must acknowledge this amendment by submitting a signed copy of this SF30 along

Continued ...

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

15C. DATE SIGNED 16B. UNITED STATES OF AMERICA 15B. CONTRACTOR/OFFEROR 16C. DATE SIGNED

(Signature of person authorized to sign) (Signature of Contracting Officer)

Rosana Yousefgoarji

STANDARD FORM 30 (REV. 10-83)

Prescribed by GSA

FAR (48 CFR) 53.243

NSN 7540-01-152-8070

Previous edition unusable

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

ITEM NO. SUPPLIES/SERVICES QUANTITY UNIT UNIT PRICE AMOUNT

NAME OF OFFEROR OR CONTRACTOR

2 2

CONTINUATION SHEET

REFERENCE NO. OF DOCUMENT BEING CONTINUED PAGE OF

(A) (B) (C) (D) (E) (F)

R17PS00307/000002

with their proposal.

NSN 7540-01-152-8067 OPTIONAL FORM 336 (4-86)

Sponsored by GSA

FAR (48 CFR) 53.110

Amendment No. 0002 to Solicitation No. R17PS00307

Shasta and Keswick Powerplants Excitation System Replacements

Central Valley Project, California

Questions and Answers

Question 1: As noticed in the technical portion of the specification it states the excitation system, which must be supplied, is the DECS-2100 system manufactured by Basler. I noticed in some sections referencing the Basler product it states “or equal” and in some it does not. There are numerous other excitation manufacturers which can supply a solution for this solicitation. Please clarify.

Response 1: The Specification Section 48 19 80 has been revised to add “or equal”.

Questions 2: We understand that the subject solicitation is an open bid, but the technical specification clearly identified the type of exciter, its brand name and the manufacturer which the

Bureau of Reclamation would like to have for these two plants. See PART 2 PRODUCTS of section 48 19 80. This solicitation is more like a sole source and it will put other exciter manufactures into a very disadvantageous competitive position under an open bid. Would the government remove such specific product requirements and allow exciters with other brand names to be proposed, or just revise it to a sole source bid?

Response 2: The Government’s intention is to use Basler or equal product. The Specification

Section 48 19 80 has been revised to add “or equal”.

Amendment 0002 Shasta and Keswick Powerplant Excitation System Replacements Specifications No. 20-C0863

Excitation Systems

48 19 80 - 1

SECTION 48 19 80

EXCITATION SYSTEMS

PART 1 GENERAL

1.01 MEASUREMENT AND PAYMENT

A. Remove and Dispose of Existing Excitation System Equipment:

1. Payment: Include cost in lump sum price offered in the Price Schedule for Removing and Modifying Existing Equipment.

a. Remove 3 excitation cabinets at Shasta Power Plant.

b. Remove 3 excitation cabinets at Keswick Power Plant.

c. Remove 3 PPT transformers at Shasta Power Plant.

d. Remove 3 PPT transformers at Keswick Power Plant.

e. Remove 4 excitation system automatic voltage regulator (AVRs) printed circuit boards and human machine interfaces (HMIs) at Shasta Power Plant (Shasta Unit Nos. 1 and 2 and Shasta Station Service Units S1 and S2).

B. Remove and Dispose of External Cabling, Metal-enclosed Bus, and Associated

Equipment:

Removing and Modifying Existing Equipment.

C. Furnish, Install, Test and Deliver New Excitation Systems:

1. Payment: Lump sum price offered in the schedule.

a. Furnish, install, and test and deliver 6 units.

1) 3 Units for Keswick Power Plant (Unit Nos. 1 through 3)

2) 3 Units for Shasta Power Plant (Unit Nos. 3 through 5)

b. Furnish, install and test and deliver digital front-end retrofit system (Shasta Unit Nos. 1 and 2 and Shasta Station Service Units S1 and S2)

1) 4 Units for Shasta Power plant will have the HMI and AVR to match the new system.

2. Payment will be made at the lump sum price offered in the Price Schedule for Excitation Systems.

D. Factory Test New Excitation Systems:

1. Payment: Include cost in lump sum price offered in the Price Schedule for Basic Electrical Materials and Methods.

48 19 80 - 2

E. Spare Parts:

1. Payment: Lump sum price offered in the Price Schedule.

F. Drawings and Data for Excitation System:

G. Progress Final (As-built) Drawings:

Project Record Documents.

H. Train Government Personnel:

I. Power Potential Transformers (PPT):

1. Payment: Lump sum price offered in the Price Schedule.

1.02 REFERENCE STANDARDS

A. American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)

1. ASHRAE 52.2-12 Method of Testing General Ventilation Air- Cleaning Devices for Removal Efficiency by Particle Size

B. ASTM International (ASTM)

1. ASTM D1535-14 Standard Practice for Specifying Color of the Munsell System

C. Facilities Instructions, Standards and Techniques (FIST)

1. FIST 3-8-11 Operation, Maintenance, and Field Test Procedures for Protective Relays and Associated Circuits

D. Institute of Electrical and Electronics Engineers (IEEE)

1. IEEE 421.1-07 Definitions for Excitation Systems for Synchronous Machines

2. IEEE 421.2-14 Identification, Testing, and Evaluation of the Dynamic Performance of Excitation Control Systems

48 19 80 - 3

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

4. IEEE 421.5-16 Excitation System Models for Power System Stability Studies

5. IEEE 421.6-16 DRAFT Recommended Practice for the Specification and Design of Field Discharge Equipment for Synchronous Machines

6. IEEE 693 – 2005 Seismic Design of Substations

7. IEEE C37.16-09 Preferred Ratings, Related Requirements and Application Recommendations for Low Voltage AC (635 and Below) and DC (3,200 V and Below) Power Circuit Breakers.

8. IEEE C37.20.1-02(2007) Metal-Enclosed Low-Voltage Power Circuit Breaker Switchgear

9. IEEE C50.13-14 Cylindrical-Rotor 50Hz and 60 Hz, Synchronous Generators Rated 10 MVA and Above

10. IEEE C57.12.01-15 Dry-Type Distribution and Power Transformers Including Those with Solid Cast and/or Resin Encapsulated Windings

11. IEEE C57.12.91-11 Test Code for Dry-Type Distribution and Power Transformers

12. IEEE C57.13-16 Instrument Transformers

13. IEEE C57.18.10-98(2008) Standard Practices and Requirements for Semiconductor Power Rectifier Transformers

14. IEEE C57.116-14 IEEE Guide for Transformers Directly Connected to Generators

E. National Electrical Manufacturers Association (NEMA)

1. NEMA ICS 5-00(2010) Industrial Control and Systems: Control Circuit and Pilot Devices

2. NEMA WC 70-09 Power Cables Rated 2000 Volts or Less for the Distribution of Electrical Energy

3. NEMA WD-12 Wiring Devices

48 19 80 - 4

F. National Fire Protection Association (NFPA)

1. NFPA 70-14 National Electrical Code (NEC)

G. Underwriters Laboratory (UL)

1. UL 489-12(2014) Molded-Case Circuit Breakers, Molded- Case Switches and Circuit-Breaker Enclosures

2. UL 1066-2004(2013) Low-voltage AC and DC Power Circuit Breakers Used in Enclosures

1.03 DEFINITIONS

Abbreviation Definition

AC Alternating Current

A/D, D/A Analog/Digital, Digital/Analog

AVR Automatic Voltage Regulator

CT Current Transformer

DC Direct Current

HXL Volts-Per-Hertz Limiter

HXP Volts-Per-Hertz Protection

KA Regulator Gain

LCD Liquid Crystal Display

LED Light Emitting Diode

OEL Over-Excitation Limiter

OEP Over-Excitation Protection

PF Power Factor

PPT Power Potential Transformer

PSS Power System Stabilizer

PT Potential Transformer

PIV Peak Inverse Voltage

SCADA Supervisory Control and Data Acquisition

SCR Silicon Controlled Rectifier

TA Regulator Time Constant

48 19 80 - 5

Abbreviation Definition

UEL Under-Excitation Limiter

UEP Under-Excitation Protection

VLIM Excitation Limiting Voltage

VAR Volt Amperes Reactive

WECC Western Electricity Coordinating Council

A. Excitation System Voltage Response Time: Time in seconds for excitation voltage to reach 95 percent of difference between rated-load field voltage and ceiling voltage.

B. One-per-unit Excitation System Voltage: Field voltage of a synchronous machine required to produce rated terminal voltage on air gap line (theoretical point) of a synchronous machine at a field winding temperature of 75 degrees C.

C. Excitation System Ceiling Voltage: DC component of maximum possible excitation system output voltage.

1.04 EXCITATION SYSTEM DESIGN REQUIREMENTS

A. Designed to utilize existing cable tray arrangements and floor penetrations where practicable.

B. Refer to drawings for layout, adjacent equipment, power and communication interconnects, and installation notes. Provide and coordinate locations of devices and routing of interconnects.

C. Modular construction to permit individual module removal for inspection, diagnostics, repair, or replacement.

D. Provide fixed or draw out type SCR bridge (power converter) design.

E. Provide interchangeable parts for the following components sized similarly for typical units.

1. SCR bridges.

2. Auxiliary transformers.

3. PPTs.

4. Excitation AC supply breaker.

5. Associated excitation system devices.

6. Digital AVR.

48 19 80 - 6

7. HMIs.

F. Designed with following features:

1. Redundant Digital AVR and firing circuits if separate.

2. AVR set point adjuster.

3. PSS, IEEE type PSS2B.

4. Manual or DC regulator (for test purposes only).

5. DC regulator set point adjuster.

6. Adjuster follower that provides set point tracking between manual and automatic modes.

7. Reactive current compensator.

8. Terminal voltage control capability.

9. Limiters:

a. HXL.

b. OEL.

c. UEL.

d. Synchronous machine terminal overvoltage limiter.

10. Redundant full wave rectifying SCR bridge(s).

11. Synchronous machine field circuit discharge equipment (crow-bar circuit).

12. Generator field voltage and current transducers.

13. Field Ground Module.

14. Excitation system power supplies: Use both rectified AC (from station service or PPT) and DC (station batteries) power sources auctioneered for excitation power (power to digital controller, excitation logic controls, and excitation protection, etc.).

15. Auxiliary relays.

16. Local control and annunciator touch-screen (one within each excitation cubicle lineup) excitation system human machine interface panels.

17. Interface with new field current and voltage dual view (analog and digital) meters.

18. Remote (at unit control boards) control switches with LED push-to-test indicating lights on unit control board:

a. Exciter ON/OFF (69ECS).

b. Voltage level adjuster (90ECS).

c. Excitation supply breaker (52ECS).

48 19 80 - 7

19. Hardware and software required to make program code changes.

20. Data logging capability.

21. Voltage and current transducers.

22. Field voltage and field current displays at unit control boards.

23. Protective relaying.

24. Protection, metering, and excitation current transformers.

25. Potential transformers within existing enclosures.

26. PPT.

27. Excitation AC power circuit breaker.

G. Provide adequate terminal points using new terminal blocks as required within unit control boards for Contractor control and separate protection interface.

1. Provide discrete protection system outputs as inputs to the excitation system limiter and protection coordination and troubleshooting on excitation system HMI.

2. Provide excitation internal trip contact interface to existing protection system as discrete input.

H. Provide new excitation system AC and DC distribution panel circuit breakers that are compatible with existing panels.

I. Provide current transformer (CT) factory test results (for all CTs related to this project).Connect to an existing synchronous machine field circuit via slip rings.

J. Replace brushes, brush holders, and other equipment associated with connection of Keswick excitation system.

K. Align and bed brushes with collector rings.

L. Continuous Capacity: 115 percent of rated generator field current, minimum.

M. Conform to applicable IEEE standards and NFPA 70.

N. Excitation systems shall be of the same type and manufacture.

O. All equipment to function up to 200 percent over speed (120 Hz) minimum.

P. Seismic qualifications: Meet high qualification level in accordance with IEEE 693.

Q. Each exciter annunciator alarm will be hardwired from the new excitation system to its corresponding annunciator alarm (located in the corresponding Main Control Room.

48 19 80 - 8

1. Shasta: From the Main Control Room Annunciator, the excitation alarms will be transmitted to the existing Governor Annunciator. The contractor will field verify cable route and cables to be replaced with new.

a. Shasta’s Unit 1 Annunciator drawing 214-D-021583, is a sample of how Units 3 through 5 annunciators will be wired by the contractor.

2. Keswick: There are no Governor Annunciators, only annunciators in the Main Control Room.

R. The contractor shall disconnect/electrically isolate and abandon the existing

Keswick rotating exciters which are located on the top of each generator.

S. The contractor will follow NERC’s requirements for Automatic Voltage Regulator/Power System Stabilizer (AVR/PSS).

1. Shasta: The contractor shall wire Units 3, 4, and 5 annunciators similar to

Unit 1’s Power System stabilizer circuit; drawing 214-D-21583.

2. Keswick: This powerplant does not have existing PSS circuits. The contractor shall design, wire and test a new PSS circuit for each Keswick excitation system. The contractor may use Shasta’s dwg 214-D-21583 as a guide.

T. Prior to each excitation system’s commissioning/testing, the Government will download the software logic into the new AVR/PSS systems for existing SCADA (Supervisory and Data Acquisition, also known as CVACS) interface.

1.05 FUNCTIONAL REQUIREMENTS

A. Supply field current required by synchronous machine to meet a specific range of power system operating conditions.

B. Quickly demagnetize synchronous field by maintaining continuous field discharge path through active “crow bar” circuit and discharge resistor in parallel with generator field windings for an adjustable time interval during normal and emergency shutdown.

C. Permit continuous stable operation of the synchronous machine for all permissible loading conditions (with unit operating either overexcited or under excited).

D. Provide synchronous machine terminal voltage tolerance under all permissible loading conditions between plus or minus 5 percent of rated voltage and 2 percent of rated frequency.

E. Provide high initial response in accordance with IEEE 421.1. SCR bridge current

48 19 80 - 9 short- time capability not less than short-time overcurrent capability of synchronous machine field windings in accordance with IEEE C50.13.

F. Provide a ceiling voltage of 150 percent of rated synchronous machine field voltage.

G. Provide rated-load field voltages and currents for transient response when the machine is between 70 and 115 percent of rated synchronous machine terminal voltage.

H. Withstand internal and external faults to the synchronous machine, abnormal operation, or emergency operation without damage to excitation equipment or machine’s electrical and magnetic circuits.

I. Prevent excitation system shutdown with unit breaker closed except for catastrophic excitation system failure.

J. Rapidly reach positive and negative ceiling voltages.

K. Provide test connection interface for diagnostics of electronic modules critical to excitation system performance.

L. Provide devices for polarizing and establishing initial magnetic flux in field circuit of synchronous machine in response to a speed signal. Field flashing power is available from 125 VDC power plant battery for initial and black start capability.

M. New Shasta Unit Nos. 3 through 5, and Keswick Unit Nos. 1 through 3 excitation system must have integral excitation cabinet bus DC lead switching capability. This is to minimize time required to swap field polarity for more even ring brush wear.

N. The Government will provide relay settings for all existing and new excitation system relays and relays that interface to the new excitation systems.

O. The Government will provide existing “onsite extraction” of current.ccf setting files and provide this information to the exciter manufacturer upon request. This information will be from Shasta’s Unit Nos. 3 through 5 and Keswick’s Unit Nos. 1 through 3. This information can be used by the exciter manufacturer’s (engineer design group) for system conversion (from the existing excitation system to its corresponding new excitation system).

1.06 SUBMITTALS

A. Submit the following in accordance with Section 01 33 00 - Submittals and Section

01 33 26 - Electrical Drawings and Data.

B. RSN 48 19 80-1, Approval Design Data.

C. RSN 48 19 80-2, Description of System Operation.

48 19 80 - 10

D. RSN 48 19 80-3, Approval Drawings and Data (Manufacturer’s Format).

E. RSN 48 19 80-4, Approval Drawings (Government Format):

1. Schematic and wiring diagrams.

F. RSN 48 19 80-5, Factory Test Procedures:

1. For each excitation system and all components including PPT, HMIs, AVRs and AC exciter field breaker.

G. RSN 48 19 80-6, Factory Test Reports:

1. Results of factory tests.

a. Instrumentation transformer tests:

1) PTs: Polarity and ratio.

2) CTs: Ratio, polarity, excitation current, and injection.

H. RSN 48 19 80-7, Field Test Reports:

1. Results of field tests.

I. RSN 48 19 80-8, Progress Final (As-built) Drawings.

J. RSN 48 19 80-9, Operation and Maintenance Instruction Books.

K. RSN 48 19 80-10, Onsite Extraction of current.ccf settings (Government submittal to Contractor):

1. Hard copy and Compact Disc (CD) to Contractor from Government.

2. Includes settings for each existing excitation system involved with this project.

L. RSN 48 19 80-11, Quality Assurance and Regulatory Documentation:

1. ISO 9001 or 9002 certifications.

2. Excitation System, power potential transformer (PPT) and power circuit breaker manufacturer’s confirmation of specialized experience and corresponding list of projects and contact information in regard to design, manufacturing and assembly of excitation systems, dry-type power transformers and power circuit breakers in the past 20 years.

a. Installers must show proof that they have been installing, interfacing and testing similar excitation systems, PPTs and power circuit breakers in the past 5 years. Documentation shall include references of past projects and contact information.

b. The contractor’s design, installation and testing Electrical Engineers shall have 5 years’ experience minimum, working with excitation systems similar to this project’s requirements.

48 19 80 - 11

3. The contractor shall provide a copy of his C-10 license from the California Contractors State License Board (CLSB).

1.07 QUALITY ASSURANCE

A. The excitation system, power potential transformer (PPT) and power circuit breaker manufacturers shall be ISO 9001 or 9002 certified.

B. The excitation system, PPT and power circuit breaker manufacturers shall have specialized experience in the design, manufacture and assembly of excitation systems, dry-type power transformers and power circuit breakers for a minimum of 20 years.

C. The excitation system and PPT installer(s) must have 5 years of experience installing, interfacing and testing similar excitation systems as what is being installed for this project. References and contact information of each past project shall be provided to BOR after Notice to Proceed.

D. The Contractor’s design, installation and testing Electrical Engineer(s) shave have 5 years’ experience minimum, working with excitation systems similar to this project’s requirements.

1.08 REGULATORY REQUIREMENTS

A. Contractor shall be licensed as classification type C-10 by the California Contractors

State License Board (CLSB).

1.09 EXISTING EQUIPMENT

A. Table 48 19 80A - Generator and Existing Excitation System Ratings shows existing equipment ratings.

Table 48 19 80A - Generator and Existing Excitation System Ratings

Units Rated App.

Power

Term.

Voltage 60Hz

PF Speed Rotating Exciter

Nameplate Output Voltage

Existing Rotating Exciter Power

Gen.

Rated Field

Current

Gen. Field Resistance

Gen. Rated Field

Voltage

[MVA] [kV] [rpm] [V] [kW] [A] [Ω] [V]

Shasta 1-5 142 13.8 1.0 138.5 320 1200 0.2679@ 75 deg C

321.5

Keswick 1-3

41.053 6.9 0.95 94.7 225 10 760 (850 max)

0.256 @ 25 deg C

48 19 80 - 12

B. Three phase fault current on:

1. Shasta:

a. Unit terminals: 66-kA symmetrical.

b. Unit terminals: 78-kA asymmetrical.

2. Keswick:

a. Unit terminals: 48-kA symmetrical.

b. Unit terminals: 58-kA asymmetrical.

3. PPT secondary: Contractor to determine.

a. Shasta:

1) Based on estimated PPT size of 770 kVA and estimated PPT secondary voltage of 400VAC.

b. Keswick:

1) Based on estimated PPT size of 305 and estimated PPT secondary voltage of 290 VAC.

1.10 PROJECT CONDITIONS

A. Altitude:

3. Keswick Powerplant Ground Level: 543.0 feet.

4. Shasta Powerplant Ground Level: 633 feet.

B. Maximum indoor ambient temperature: 40 degrees Celsius.

1.11 EXTRA MATERIALS

A. Spare Parts:

1. Deliver spare parts to locations as directed by the OGR.

2. Deliver spare parts within seven days after the installation of those parts for which spares are required.

3. Furnish spare parts per facility listed in Table 48 19 80B - Spare Parts:

Table 48 19 80B - Spare Parts

Item Description Quantity

1 Auxiliary relays, complete with any add-on auxiliary switches

One of each type

2 AC contactors/breaker, complete with any add-on auxiliary switches

One set of each type

48 19 80 - 13

Item Description Quantity

3 Assembled 3-phase module of SCRs, diodes, and fuses One set of each type

4 Assembled 3-phase module of firing circuits for SCR bridges

One of each type

5 Individual diodes Three of each type

6 Protective relays Two of each type

7 Cooling fan sets Two of each type and style

8 Transducers and transmitting devices Two of each type

9 Complete fuse units used with the equipment Six of each type, style, and ti 10 Printed circuit boards (same revision level as installed boards) Two of each

11 Control transformers Two of each type and style

12 Touch-screen control panel HMI display module and cable

Three of each type and style

13 LED indicator lamps Six of each color, type, d t l 14 Power supplies Two of each type

15 AVR, controller with all associated limiters and manual regulator

Two of each type

16 Hardware and software required to make program code changes for controller and/or PLC

One set

17 Excitation power circuit breaker One

18 PPT – 3 phase unit and enclosure One

19 Brushes (Keswick Only) 25 % of existing

48 19 80 - 14

Item Description Quantity

20 Brush holders (Keswick Only) 25% of existing

PART 2 PRODUCTS

2.01 DECS 2100 EXCITATION SYSTEM

A. Digital Static Excitation System, Type DECS-2100 manufactured by Basler

Electric, 12570 State Route 143, Highland, IL, 62249-1074 or equal; having following essential characteristics:

1. Location Units 3 through 5 at Shasta Power Plant and Units 1 through 3 at Keswick Power Plant.

2. Dual-control channel:

a. (2) Independent logic schemes.

b. Main and redundant printed circuit modules.

c. Continuously monitor the system.

d. Redundant power supplies.

e. (2) Potential transformer inputs.

3. Redundant SCR bridges.

4. HMI Type IDP-1201 kit customized by Basler Electric, or equal; 12570 State Route 143, Highland, IL, 62249-1074, or equal; having following essential characteristics:

a. Finger-safe.

b. 12.1-inch high-resolution color touchscreen.

c. Basler factory configured settings or equal.

d. Customized for mounting on the door of the existing ECS2100 system.

e. Provide uniform HMI and programming logic for Shasta Power Plant Excitation Systems.

5. Automatic voltage regulator (AVR).

6. Manual regulator (field current regulation).

7. Power System Stabilizer.

8. IRIG-B synchronizing dedicated port.

9. Network time protocol (NTP) time synchronizing via Ethernet Port.

10. Real time monitor of up to 6 parameters for commissioning, 48 19 80 - 15 troubleshooting, and NERC validation testing.

11. Non-volatile memory data logging and oscillography.

12. Frequency test response provisions with multiple input selections.

13. 10BaseT/100BaseTx Ethernet port.

14. USB port for BESTCOMS™ Pro interface.

15. USB port for event recording extraction.

16. 8 Port Ethernet Switch.

17. Necessary mounting hardware and terminations.

18. Modular design capable of interfacing with existing control, power, and instrumentation cables.

19. Provide new SCR bridges, PPT, excitation power circuit breaker, and associated devices manufactured by Basler Electric or equal, or assembled within their factory as part of a DECS2100 Static Excitation System or equal.

20. Provide features, testing, manuals, and training outlined in other applicable articles of this specification.

21. DMP3 compatible.

2.02 DIGITAL FRONT-END RETROFIT SYSTEM

A. Digital Front-End ECM-2 Controller Retrofit Upgrade Kit, Type DECS-2100 manufactured by Basler Electric, 12570 State Route 143, Highland, IL, 62249- 1074, or equal; having following essential characteristics:

1. Location Units 1 and 2 and Station Service Units S1 and S2 at Shasta Power Plant.

2. Dual-control channel:

a. (2) Independent logic schemes.

b. Main and redundant printed circuit modules.

c. Continuously monitor the system.

d. Redundant power supplies.

e. (2) Potential transformer inputs.

3. HMI Type IDP-1201 kit customized by Basler Electric, 12570 State Route 143, Highland, IL, 62249-1074 or equal; having following essential characteristics:

a. Finger-safe.

b. 12.1-inch high-resolution color touchscreen.

c. Basler factory configured settings or equal.

48 19 80 - 16

d. Customized for mounting on the door of the existing ECS2100 system.

e. Provide uniform HMI and programming logic for Shasta Power Plant Excitation Systems.

4. Automatic voltage regulator (AVR).

5. Manual regulator (field current regulation).

6. Power System Stabilizer.

7. Configured for two SCR bridges.

8. Voltage regulation accuracy improved 0.1 percent compared to existing Eaton ECS2100.

9. Fiber Optic Cable and Connector Kit.

10. IRIG-B synchronizing dedicated port.

11. Network time protocol (NTP) time synchronizing via Ethernet Port.

12. Real time monitor of up to 6 parameters for commissioning, troubleshooting, and NERC validation testing.

13. Non-volatile memory data logging and oscillography.

14. Frequency test response provisions with multiple input selections.

15. 10BaseT/100BaseTx Ethernet port.

16. USB port for BESTCOMS™ Pro interface.

17. USB port for event recording extraction.

18. 8 Port Ethernet Switch.

19. Necessary mounting hardware and terminations.

20. Modular design capable of interfacing with existing control, power, and instrumentation cables.

21. Interface with existing SCR bridges, PPT, and excitation power circuit breaker.

22. Provide retrofit drawings containing complete interface with existing ECS2100 equipment and interface equipment.

23. Provide features, testing, manuals, and training outlined in other applicable articles of this specification.

24. DMP3 compatible.

2.03 CUBICLES

A. Type: NEMA 12 enclosure for indoor application as shown.

B. Material: Manufacturer’s standard gauge sheet steel.

48 19 80 - 17

C. Locations: As shown.

D. Structural Requirements:

1. Hinged doors for access to internal equipment with top and bottom latches.

2. Adequate louvers for ventilation.

3. Floor mounting frames if applicable.

E. Designed for top entry of all control cables, power cables, communications cables, and metal-enclosed busway. Provide sufficient space to accommodate number and size of incoming cables and bus.

F. Provide terminal blocks at shipping splits.

G. Provide dedicated terminal section for external wiring, which can be included in the low- voltage logic control cubicle.

H. Provide provisions for hinged 19-inch rack mounted external excitation supply protective relays and other devices in PPT enclosure or adjacent dedicated cubicle.

I. Provide firewall at interfaces between metal-enclosed bus, excitation AC supply breaker, cable entry, instrumentation transformers, and major enclosures to include excitation system, and PPT cubicle.

1. Minimum average ignition time: 60 seconds.

2. Maximum average burning time: 500 seconds.

J. Provide metal barrier between low-voltage and high-voltage compartments (to include the excitation supply breaker).

K. Provide pre-drilled copper ground bar in each cubicle.

L. Accessories:

1. 120 Volt, 60 Hertz, duplex NEMA 5-15R receptacle mounted in each cubicle.

2. 120 Volt, 60 Hertz, fluorescent lighting fixture mounted in each cubicle and controlled by switched automatically with door.

3. Provide adequate space heaters to prevent moisture condensation inside cubicles at all times. Controlled by thermostat.

4. Provide cabinet ventilation fans capable of keeping the enclosure below 104 degrees F.

5. Provide cabinet air filters with a Minimum Efficiency Reporting Value (MERV) rating of 8 as defined in ASHRAE 52.2. Air filter media shall be removable and replaceable.

48 19 80 - 18

2.04 POWER POTENTIAL TRANSFORMER (PPT)

A. In accordance with IEEE C57.12.01 and IEEE C57.12.91.

B. Type: Vacuum pressure impregnated (VPI) or vacuum pressure encapsulated

(VPE), dry-type.

C. Ratings:

1. Rectifier duty.

2. Power rating: Determined by Contractor.

3. Cooling Class: Class AA.

4. Temperature rise: 150 degrees Celsius.

5. Frequency: 60 Hertz.

6. Phases: 3.

7. High voltage winding:

a. Shasta: 13,800 Volts.

b. Keswick: 6,900 Volts.

8. Low voltage winding: Determined by Contractor.

9. High voltage winding connection: Determined by Contractor.

10. Low voltage winding connection: Delta connected.

11. High voltage winding BIL:

a. Shasta: 95 kilo-Volts minimum.

b. Keswick: 60 kilo-Volts minimum.

12. Low voltage winding BIL:

a. Shasta: 20 kilo-Volts minimum.

b. Keswick: 20 kilo-Volts minimum.

13. Primary short circuit withstand:

a. Shasta:

1) Unit terminals: 66-kA symmetrical.

2) Unit terminals: 78-kA asymmetrical.

b. Keswick:

1) Unit terminals: 48-kA symmetrical.

2) Unit terminals: 58-kA asymmetrical.

14. Secondary short circuit withstand:

a. Momentary current: Contractor to determine per facility.

48 19 80 - 19

b. Short time current: Contractor to determine per facility.

D. Keswick must fit inside existing foot print of:

1. 92” High

2. 52” Deep

3. 84” Wide

4. This includes space for the excitation power circuit breaker.

5. If the new PPT is placed in the same location as the existing PPT, the new PPT must be 3 inches from the existing white tape located on the floor (next to the existing PPT). The white tape allows turbine pit access for future maintenance. The contractor shall verify that the new PPTs fit within these specified boundaries.

6. The contractor also has the option to install the new PPTs in the corresponding new excitation system cabinets. If the contractor choses this route, the contractor shall confirm and modify the bus and cable routings for the high and low sides of each new PPT.

E. Shasta’s PPT foot print is:

1. 90” High

2. 60” Deep

3. 120” Wide

F. Core:

1. High magnetic permeability, cold-rolled, grain oriented with low hysteresis losses.

2. Magnetic flux density at rated conditions sufficiently below saturation point to be optimally energy efficient.

3. Corner joints manufactured to minimize core losses, excitation current, and noise levels to a minimum.

G. Windings:

1. Supported by bottom supports and spacer.

2. Hygroscopic insulation not allowed.

3. Winding connection:

a. Minimize potential fault currents in PPT circuits.

b. Isolate harmonic content.

H. Conductors: Copper, able to operate with all loads and temperature rise limitations

48 19 80 - 20 of IEEE C57.12.01.

I. Enclosure: Rigid metal, self-supporting, enclosed for indoor use.

J. Nameplates:

1. Diagrammatic nameplate in accordance with IEEE C57.12.01 Table 13.

2. Provide additional nameplate for project specific designation per this section.

K. Provide lifting lugs, pulling eyes, and jacking pads for lifting and moving.

L. Accessories:

1. Manufacturer diagrammatic nameplates for all auxiliary transformers and appropriate separate devices.

2. Ground pad, with two bolted-type connectors, suitable for connecting No. 4/0 AWG stranded bare-copper cable.

M. RTD: 100 ohm, 3 lead, platinum, dual-element. Mount two RTDs per each low voltage and high voltage winding phase. One RTD per winding will be spare.

N. Perform at or below 50 decibel maximum noise level in accordance with

IEEE C57.12.01.

2.05 PPT PROTECTIVE RELAY

A. PPT Type SEL 0787 Generator Relay manufactured by Schweitzer Engineering

Laboratories, 2350 NE Hopkins Ct., Pullman, WA 99163; or equal, having following essential characteristics:

1. Control input voltage: 125 VDC.

2. Differential current protection.

3. Instantaneous and time overcurrent protection.

4. Negative sequence overcurrent protection.

5. Provide DC field overcurrent protection using a properly coordinated excitation supply AC overcurrent, which is proportional to the DC field overcurrent.

6. Single relay assembled with rack mount bracket.

7. Modbus protocol requirements:

a. Serial RS-232 RTU or ASCII mode,

b. up to 38K bps,

c. 8 data bits,

d. none parity, 48 19 80 - 21

e. One stop bit,

f. Analog input data must be in 16 bit integer format.

g. Support the following function codes:

1) Read coil status – Function code 01,

2) Read input status – Function code 02,

3) Read holding register – Function code 03,

4) Read input register – Function code 04.

8. RTD module.

a. Alarm on temperatures above 175 degrees C.

b. Trip generator lockout on temperatures above 187 degrees C.

B. Locate PPT protective relay within dedicated section of PPT enclosure, adjacent separate PPT cabinet.

2.06 STANDALONE FIELD GROUND RELAY

E. Type BE1-64F manufactured by Basler Electric, 12570 State Route 143, Highland, IL, 62249-1074; or equal, having following essential characteristics:

1. Provide when SEL multifunction generator protection relay does not exist.

2. Detect and annunciate a ground path on field winding developed during operation.

3. Test function.

4. Two-level detection for pre-alarm and trip.

5. Nonvolatile storage of trip target state.

6. Provide time delay features to allow for start-up procedures when field flashing is active.

7. Provide with two sets of electrically separate contacts that close when field ground detector pre-alarm and trip levels are active. Wire contacts out to terminal blocks for use with Government alarm circuits.

8. Provide 120 Vac UPS power supply circuit.

2.07 FIELD GROUND RELAY SYSTEM

A. Type SEL 2664XX2XXX Field Ground Module manufactured by Schweitzer

Engineering Laboratories, 2350 NE Hopkins Court, Pullman, WA 99163; or equal, having the same essential characteristics.

1. Location: Excitation system cubicle.

2. Provide when existing compatible SEL multifunction relay exists (i.e.

48 19 80 - 22

SEL 300G).

3. Fiber Optic Cable capability/interface for future fiber optic cable (fiber optic cable is not part of this specification).

4. New control cable from excitation cubicle to unit control board and required accessories.

B. Type SEL 2812M Fiber-Optic Transceiver (as required) with IRIG-B manufactured by

Schweitzer Engineering Laboratories, 2350 NE Hopkins Court, Pullman, WA 99163; or equal, having the same essential characteristics.

1. Purpose: Fiber-optic transceiver for communication between existing SEL 300G and SEL 2664.

C. Type SEL C805 Optical fiber (200µm) Multi mode fiber-optic cable and jumpers manufactured by Schweitzer Engineering Laboratories, 2350 NE Hopkins Court, Pullman, WA 99163; or equal, having the same essential characteristics.

1. Purpose: Interconnection of SEL2664 to SEL generator protective relay.

2. Cable type: Multi-Mode.

3. Major cable components:

a. UL Riser rated.

b. Dielectric outer cable.

c. Meets IEEE 802.3ae standards.

d. Zipcord and heavy-duty PVC-jacketed fiber.

e. Loose-tube.

f. Gel-free.

g. Attenuation: Directly proportional to cable length for an arbitrary cable length section after steady-state conditions are reached.

h. Color coded per TIA/EIA-598.

4. Cable core: Symmetrically stranded buffer tubes around dielectric central member.

5. End termination: V-System or ST.

6. Cable tensile strength:

a. Long term (installed): 135 pounds.

b. Short term (during installation): 600 pounds.

7. Operating temperature range: -20 to 80°C.

2.08 PPT METERING SECTION

48 19 80 - 23

A. Design to accommodate the following instrumentation transformers:

1. High voltage side protective relay CTs.

a. Ratio:

1) Shasta: 50:5 amperes.

2) Keswick: 50:5 amperes.

b. Accuracy class: 0.6B0.1 C15.

c. Window type.

d. Voltage: 600 volts.

e. Thermal rating: 1 at 55 degrees Celsius.

2. Low voltage side protective relay CTs.

a. Location: Load side of excitation supply breaker within excitation system cubicles.

b. Ratio:

1) Shasta: 1,200:5 amperes.

2) Keswick: 800:5 amperes.

c. Accuracy class: C400.

d. Window type.

e. Voltage: 600 volts.

f. Thermal rating: 1 at 55 degrees Celsius.

2.09 REPLACEMENT POTENTIAL TRANSFORMERS

A. High voltage side regulating and metering PTs (one per phase, six total per unit):

1. Location: Generator 13.8kV bus within existing rack out enclosures.

2. Voltage: 14400/120 Volts, 3 phase capable of 125 percent of rated voltage.

3. Conform to IEEE C57.13

4. BIL: 95 kV

5. Accuracy class: 0.3 (W, X, M, Y, Z, ZZ) minimum.

6. Thermal rating: 1000 VA minimum at 55 degrees Celsius.

7. Connection: Match existing.

2.10 EXCITATION POWER CIRCUIT BREAKER

A. Voltage: Low voltage side of PPT.

B. Location: Dedicated cubicle inside of or adjacent to PPT cabinet.

48 19 80 - 24

C. Interrupting Rating:

1. Contractor to determine rating based on PPT size and percent impedance.

2. Minimum interrupting rating:

a. Shasta: 1,200 amperes RMS symmetrical.

b. Keswick: 800 amperes RMS symmetrical.

D. Type:

1. Shasta: Electrically operated, draw-out type with remote racking capability.

2. Keswick: Electrically operated, draw-out with remote racking capability or fixed type.

E. Operating Mechanism: Trip free, two-step stored energy type with quick make, quick break option. Provide common tripping of all poles.

F. Interrupting Mechanism: Arc chutes with steel vent grids to suppress arcs and cool off vented gases.

G. Breaker Control Power: 125-volt DC.

H. Provide at least 5 “a” and 5 “b” auxiliary switch contacts that are adjustable in circuit closing or opening mode.

1. Connect to external control, protection and annunciation circuits as necessary.

I. Arrange for remote control of close and trip functions.

J. Provide breaker auxiliary contact for control circuit for operation of remote red and green indicating lights. Do not use contacts from breaker control switch to operate indicating lights.

K. Operation:

1. Normal shutdown of exciter: Do not trip excitation supply breaker.

2. Load rejections: Do not trip breaker if synchronous machine can be expected to recover without shutdown.

3. Emergency shutdown or malfunction of exciter: Trip excitation supply breaker to protect PPT from fault currents associated with exciter malfunction.

L. Conform to UL 1066 or 489, IEEE C37.16, and IEEE C37.20.1.

M. Although the existing Keswick exciter breakers are called #41E, the new replacement breakers will be named #52E, not #41E where “#” is the generator number 1, 2 or 3.

48 19 80 - 25

2.11 SCR BRIDGES

A. Type: Three-phase, full-wave rectifier bridge assemblies.

B. Configuration: Two SCRs per phase, six SCRs per bridge.

C. Essential Characteristics:

1. Provide redundancy such that failure of one bridge shall not cause shutdown of the synchronous machine or result in reduction of machine capacity;

therefore, redundant bridges and firing circuits shall operate continuously and in parallel at all times to insure bump less transfer to functioning redundant bridges.

2. Provide two sets of electrically separate output contacts for bridge failure.

3. Rated to incorporate an allowance to cover any loss in capacity due to aging and fault duty.

4. PIV rating of at least 3.5 times peak input voltage for protection against reverse transients.

5. Transient voltage protection for bridge circuit to guard against SCR damage under all operating conditions. If fuses are used, they shall be equipped with visual blown-fuse indicators and that have electrically separate contacts, wired out to terminal blocks for Shasta. Have indicating lights and test points located on circuit boards furnished with SCR bridges.

6. Separate temperature-detecting device in each AC bridge circuit branch with three electrically independent alarm and trip contacts that close when temperature of bridge circuit rises to a preset level. Wire contacts out to terminal blocks for annunciation, supervisory control, and shutdown circuits.

7. Separate firing circuits controlled by voltage regulating equipment if required by manufacturer design.

D. Forced Ventilation System:

1. Design to require no forced ventilation for start-up and off-line operation.

Forced ventilation may be activated when synchronous machine is on-line and carrying load.

2. Fans:

a. Redundant fan sets.

b. Mount on each bridge.

c. Satisfy bridge heat sinking requirements in all operational modes.

d. Primary fan power supply: AC (PPT).

e. Secondary fan power supply: DC (station batteries).

48 19 80 - 26

3. Provide two power sources to fans with automatic switching between the two sources. Provide capability to switch for testing.

4. Switch power sources when primary power source is failing or is outside of its design voltage or frequency range.

5. Provide two electrically separate auxiliary contacts on each fan contactor.

a. One Normally Open contact.

b. One Normally Closed contact.

c. Wire contacts to terminal blocks.

6. Provide direct-acting devices for detecting loss of air flow with monitoring powered by 125 VDC. Do not use differential pressure- or temperature-sensing devices. Provide contacts from AVR software or direct-acting detectors, wired-out to terminal blocks, to annunciate loss of fan or power supply on loss of forced ventilation in SCR bridge circuits.

E. Performance:

1. Short-time thermal overload capability equal to or greater than the rotor winding short-time thermal overload requirements specified in IEEE C50.13.

2. Capable of continuously supplying 115 percent of rated generator field current.

2.12 FIELD CIRCUIT EQUIPMENT

A. Synchronous machine field current transducer:

1. Type VT7-016E manufactured by Ohio Semitronics, Inc., 4242 Reynolds Drive, Hilliard, Ohio, 43026; or equal, having the following essential characteristics:

a. Provide field current transducer output signals for use with new meters on unit control board and for SCADA input.

b. Maintain isolation from ground and field circuit components.

c. Isolation: 2500 volts minimum.

d. Input: 0-100 millivolt shunt which represents 0-1,400 amperes DC (Shasta) and 0-800 amperes DC(Keswick)

e. Output: 4-20 milli-ampere over impedance range of 0 to 500 ohms without necessary adjustments.

f. Accuracy: Plus or minus 0.5 percent of rated full scale dc output, maximum.

g. Field adjustable calibration: Plus or minus 10 percent of rated output.

48 19 80 - 27

B. Provide new field current shunt resistors or other adequate field current sensing devices. Install new shunt on generator field side to show current decay when discharge circuits are active.

C. Synchronous machine field voltage transducer:

1. Type CT8-014E manufactured by Ohio Semitronics, Inc., 4242 Reynolds Drive, Hilliard, Ohio, 43026; or equal, having the following essential characteristics:

a. Provide field voltage transducer output signals for use with new meters on unit control board and for SCADA input.

b. Maintain isolation from ground and field circuit components.

c. Isolation: 2500 volts minimum.

d. Input: ±600 volts DC.

e. Output: 4-20 milli-Ampere output over impedance range of 0 to 500 ohms without necessary adjustments.

f. Accuracy: Plus or minus 0.5 percent of rated full scale dc output, maximum.

g. Field adjustable calibration: Plus or minus 10 percent of rated output.

D. Electronic discharge equipment shall be used to discharge generator field and shall consist of the following:

1. Active “Crow Bar”: A controllable semiconductor switch in series with a non- linear or linear discharge resistor or silicon carbide MOV to limit transient currents during de-excitation for each emergency shutdown of synchronous machine.

a. Anti-parallel SCRs in semiconductor switch: Provided with appropriate instantaneous ratings to conduct synchronous machine field discharge currents limit only by synchronous machine field winding resistance and non-linear or linear discharge resistor connected in series. Force “Crow Bar” SCRs to conduct during emergency shutdown via a gate control signal that is independent of field voltage or current gate signal.

1) Prevent the DC field current from free-wheeling through the SCR Bridge by using a block, trigger, trip sequence for initiating the crow bar.

a) Block SCR bridge gate firing pulses immediately after receiving the unit lockout condition.

b) Energize the crowbar gating circuits to activate the crowbar.

c) Open the 52E (excitation supply breaker) following

48 19 80 - 28 an adjustable 0-10 second time delay energize timer.

i. Provide one internal AVR timer and separate external timer.

2. Provide a DC over-voltage activated or passive (i.e. MOV) crow-bar circuit.

3. Non-linear or linear Discharge Resistor Sizing: Conform to IEEE C37.18.

4. Provide contacts that close when passive de-excitation is active, wire contacts out to terminal blocks for use with lockout (86) circuits and alarm circuits.

E. Synchronous machine field winding temperature:

1. Provide device to calculate field winding resistance from field current and field voltage transducer signals during operation.

2. Display field winding temperature in degrees Fahrenheit based on the resistance derived from the calculation above on excitation system HMI.

3. Provide analog 4-20 milliamperes output for future monitoring and control board indication and on SCADA input.

4. Provide output contact for alarming when field temperature rise exceeds 60 degrees Celsius.

2.13 VOLTAGE REGULATING EQUIPMENT

A. Type:

1. Digital logic.

2. Continuously acting digital type with solid-state components.

3. Manual (DC) and automatic AC, control modes.

B. General Description and Operation:

1. Responsive to synchronous machine terminal voltage in automatic mode and be able to initiate corrective action for a sustained 0.1 percent change in terminal voltage.

2. Failure of any control element shall not cause dangerous or uncontrollable operation of the excitation system.

3. Activate alarms under abnormal conditions to warn of impending protective action, including operation of any limiters. Self-resetting alarms if conditions return to normal operating range.

C. Manual (DC) Regulator:

1. Regulate field current (preferred method), field voltage, or firing angles of SCRs.

2. Control range: 20 to 115 percent of rated synchronous machine field current.

48 19 80 - 29

3. Designed for synchronous machine testing purposes.

4. Continuously track AVR settings.

D. Manual (DC) Digital Level Reference Adjuster:

1. Can be integral to digital controller.

2. Digital level reference adjuster for smooth (or in steps of less than 0.1 percent) control of synchronous machine output field current between 20 and 115 percent of rated field current at 75 degrees Celsius. Provide rate of change capability between 0.2 to 2 percent per second. Make provisions to permit operating range shifting after adjuster is installed.

3. Adjustable operational range.

4. Be suitable for 125-volt DC operation.

5. Reposition to determined preposition (speed-no-load) voltage setting following load rejections and normal or…