(F) Basis of Design.pdf

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WESTON & SAMPSON ENGINEERS, INC.

100 International Drive, Suite 152 Portsmouth, NH 03801 tel: 603.431.3937

Bas i s o f Des i gn Repo r t

October 2024

B564 Install Permanent Generator

100% Design Submittal

Norfolk, VA

Naval Submarine Base New London Groton, CT

Building 564 Permanent Generator

Basis of Design Report October 30, 2024

Delivery Order N4008523F6272 IDIQ contract N40085-21-D-0005

A/E Services in the NAVFAC Mid-Atlantic Area

Weston & Sampson Engineers, Inc.

Perese.Gerald Image

Naval Submarine Base New London – Groton, CT Building 564 Permanent Generator Basis of Design

October 30, 2024

NAVFAC

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TABLE OF CONTENTS

Page

TABLE OF CONTENTS ...................................................................................................................... i

LIST OF FIGURES ............................................................................................................................ iii

LIST OF TABLES .............................................................................................................................. iii

LIST OF ACRYONYMS ..................................................................................................................... iv

1.0 INTRODUCTION .......................................................................................................... 1-1

1.1 Project Objectives .................................................................................................... 1-1

1.2 Project Location ........................................................................................................ 1-1

1.3 Existing Conditions ................................................................................................... 1-2

1.3.1 Existing Building 564 Power System Description .................................................. 1-2

1.3.2 Existing Building 564 Portable Generator and Manual Transfer Switch ................. 1-3

1.3.3 Existing Building 564 Main Electrical Room 115 Existing Conditions .................... 1-3

1.3.4 Existing Second Floor Electrical Equipment .......................................................... 1-4

1.3.5 Existing Exterior Electrical Equipment .................................................................. 1-4

1.3.6 Existing Building 564 Portable Generator Operation and Transfer Arrangement ..1-5

2.0 PROPOSED NEW GENERATOR AND POWER SYSTEM .......................................... 2-1

2.1 Description of the Proposed Power System .............................................................. 2-1

2.1.1 Existing Portable Generator to Remain ................................................................. 2-1

2.2 Removal and Replacement of Existing Equipment and New Equipment ................... 2-2

2.2.1 Removal of Existing MTS and Associated Feeders .............................................. 2-2

2.2.2 Existing Transformer T2 and Panel RP-2.............................................................. 2-2

2.2.3 Existing Transformer T6 and Disconnect Switch Replacement ............................. 2-2

2.2.4 New ATS and Associated Feeders ....................................................................... 2-2

2.3 New Permanent Generator ....................................................................................... 2-3

2.3.1 New Permanent Generator Location and Auxiliary Requirements......................... 2-3

2.3.2 New Permanent Generator Rating ........................................................................ 2-3

2.3.3 Main Switchboard Feeder Breaker to MCC and Inrush Current Review ................ 2-6

2.4 Generator and New Exterior Equipment Grounding .................................................. 2-7

2.5 New Permanent Generator - Controls and Annunciator(s) ........................................ 2-8

2.5.1 Return of Normal Supply and ATS Operation ....................................................... 2-8

2.5.2 Permanent Generator and ATS Maintenance Operation ....................................... 2-8

2.5.3 Generator and ATS Annunciators ......................................................................... 2-8

3.0 ARCHITECTURAL ....................................................................................................... 3-1

4.0 MECHANICAL .............................................................................................................. 4-1

5.0 CIVIL / SITE ................................................................................................................. 5-1

5.1 Excavation for New Generator .................................................................................. 5-1

6.0 STRUCTURAL ............................................................................................................. 6-1

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6.1 New Generator Concrete Pad .................................................................................. 6-1

6.2 Exterior Building Conduit Supports ........................................................................... 6-1

7.0 ENVIRONMENTAL, PERMITS AND AUTHORIZATIONS ............................................ 7-1

7.1 Environmental .......................................................................................................... 7-1

7.2 Permits and Authorizations by NAVFAC ................................................................... 7-1

8.0 INDUSTRY STANDARDS AND REFERENCES .......................................................... 8-1

October 30, 2024 iiiwestonandsampson.com

LIST OF FIGURES

Figure 1-1..............................................................................................Aerial View of Project Location

Figure 2-1.................................................................Switchboard Breaker Timer Current Curve (TCC)

LIST OF TABLES

Table 2-1 ...............................................................................................................Generator Size Data

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LIST OF ACRONYMS

ACRONYM DEFINED TERM

A Amps / Amperes ACOE Army Corps of Engineers AIC Amperes Interrupting Capacity AF Amp Frame AT Amp Trip ANSI American National Standards Institute ATS Automatic Transfer Switch AWG American Wire Gauge CFR Code of Federal Regulations FEMA Federal Emergency Management Agency IEEE Institute of Electrical and Electronics Engineers FLA Full Load Amperes FLC Full Load Current ft2

Square Feet GPR Ground Penetrating Radar HMI Human Machine Interface HP Horsepower kAIC Thousands of Amperes Interrupting Capacity kV Kilovolt KV (One) Thousand Volts kVA Kilovolt-Ampere kW Kilowatt LRA Locked-Rotor Amperes LRC Locked Rotor Current LF Linear Feet MTS Manual Transfer Switch MVA Megavolt-Amps MW Megawatt NAVFAC Naval Facilities Engineering Systems Command NEC National Electrical Code NEMA National Electrical Manufacturers Association NFPA National Fire Protection Association O&M Operations & Maintenance SCADA Supervisory Control and Data Acquisition UFC Unified Facilities Criteria V Volts VFD Variable Frequency Drive W&S/Weston & Sampson Weston & Sampson Engineers, Inc.

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1.0 INTRODUCTION

Through delivery order N4008523F6272, Project Building 564 Permanent Generator under Weston & Sampson Engineers, Inc. IDIQ contract N40085-21-D-0005 for A/E Services for Multi-Discipline Utility Design in the NAVFAC Mid-Atlantic Area of Responsibility (AOR) located primarily at Northeast AOR, Weston & Sampson is developing a design for new permanent generator associated with Building 564 at the Naval Submarine Base New London in Groton, CT.

1.1 Project Objectives

The project objectives are to install a diesel fuel based permanent generator at Building 564 to provide standby power supporting the building in the event of a loss of power to the building, specifically the existing motor control center. The new permanent generator system will include a new automatic transfer switch to automatically start and run the generator in the event the building power loss. The new permanent generator is planned to be installed behind building 564 in an outdoor enclosure. The project includes maintaining the existing temporary portable generator presently supporting the building, with improvements to the connection point.

1.2 Project Location

The project is located at existing building 564 at the Naval Submarine Base in Groton, CT located on the Thames River.

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Figure 1-1: Aerial View of Project Location. (Building 564 outlined in red)

1.3 Existing Conditions

The building 564 permanent generator project’s purpose is to install a dedicated standby generator to support a portion of the existing building’s power system. The existing conditions of the building power system and equipment are described below.

1.3.1 Existing Building 564 Power System Description

Building 564 electrical power system is derived from the facility power system through pad mounted transformer TX-564 located in the rear of the building with markings indicating the transformer is rated at 1500 kVA and matches the size shown on the drawings provided by NAVFAC and the facility.

The 480Y/277 Volt - 3 phase 4 wire transformer secondary extends to the building main switchboard located within Electrical Room 115. The main switchboard has the following characteristics and feeders;

GE type Spectra Series main switchboard with two (2) vertical sections that are only front accessible, with an ammeter, ammeter switch, voltmeter and voltmeter switch.

The switchboard main bus is rated at 2,000 Amps, 480Y/277 Volts, 3 Phase, 4 Wire, 50 kAIC.

The switchboard includes a 2,000 Amp main circuit breaker with 2,000 Amp plug based electronic trip unit and integral long time, short time, instantaneous and ground fault protective functions.

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The switchboard includes the following feeder circuit breakers;

o Transformer T1 100 AF / 70 AT o Power Panel PP-1 250 AF / 225 AT o Transformer T2 / Panel RP-2 100 AF / 70 AT o Future Chiller 250 AF / 250 AT (In Off position) o MCC 600 AF / 600 AT o Future MCC 600 AF / 600 AT (In Off position) o Chiller #1 400 AF / 300 AT o Unlabeled 250 AF / 225 AT (In Off position) o Industrial Air Compressor 150 AF / 125 AT o Spare 150 AF / 125 AT

The 600 Amp feeder breaker in the main switchboard feeds a motor control center (MCC) though a manual transfer switch (MTS). The MCC feeds various mechanical, HVAC and process equipment within the building. The second line side connections to the MTS are connected to a portable generator located in the rear of the building.

1.3.2 Existing Building 564 Portable Generator and Manual Transfer Switch

The Main Switchboard includes a 600 Amp feeder breaker with feeder conductors that extend through a wireway from the bottom right of the switchboard to the Manual Transfer Switch (MTS) located adjacent to the switchboard in Electrical Room 115. The MTS is a 600 Amp, 3 pole, double throw switch with on-off-on positions. Note the drawings provided to Weston & Sampson indicate the MTS is a 4 pole device implying a switched neutral conductor, however as observed the switch the includes 3 poles which implies the portable generator is not a separately derived source.

The MTS includes a key interlock on the operating handle to a lock on the circuit breaker outdoors in close proximity to the portable generator at the transformer pad. The key is captured in the key interlock at the MTS and the lock at the circuit breaker appears to accept the key in order for the breaker to be permitted to close.

The load connection of the MTS feeds a Main Lug Only (MLO) connection motor control center (MCC) that is located in Electrical Room 115.

1.3.3 Existing Building 564 Main Electrical Room 115 Existing Conditions

Electrical Room 115 includes the following additional electrical equipment and items;

Power Panel PP-1

Power Panel PP-3

Receptacle Panel RP-1

Receptacle Panel RP-3

PLC Cabinet for control of various building motors

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5 kVA transformer T6 with two (2) secondary disconnect switches associated with “CMCS 120 Volt Power” and Fire Alarm Pre-Action King Fisher Panels”. Transformer T6, and disconnect switches are located immediately to the right of the MCC.

1.3.4 Existing Second Floor Electrical Equipment

There are several pieces of electrical equipment located on the second floor of building 564 including transformer T-2 that feeds panel RP-2. Presently RP-2 is not powered from the existing portable generator. NAVFAC project manager and the facility manager recently determined that the loads on RP-2 need to be supported from the new generator. Panel RP-2 operates at 208Y/120 Volts and is fed from transformer T-2 with a 480 Volt primary connected to the main switchboard.

1.3.5 Existing Exterior Electrical Equipment

Existing building pad mount transformer TX-564 is located in the rear of the building on a concrete pad.

At the same concrete pad as TX-564 is the generator circuit breaker and a generator disconnect switch with integral power plug and flexible connection to the portable generator that is parked adjacent to transformer TX-564. Below are the observations and equipment at the concrete pad;

There is a utility style kWh meter that appears to be connected to transformer TX-564 secondary, located external to the transformer enclosure with a conduit extending out of the transformer believed to be the current and voltage inputs into the meter.

Two (2) 3/4" conduits extend out of the kWh meter routed on top of the transformer dike wall and down into the concrete. It is believed these conduits include communications circuits for remote monitoring and data collection of the kWh meter.

Mounted to the side of transformer TX-564 is a load center panel, two (2) duplex receptacles and a single cord / plug type connection to the portable generator.

The load center panel appears to be rated at 208Y/120 volts and fed directly from the secondary of adjacent transformer TX-476 serving building 476. A conduit extends from TX-476 enclosure to an enclosed circuit breaker mounted next to transformer TX-476. A conduit extending from the enclosed breaker is routed across TX-476 and TX-564 transformer pads to the load center.

The rating of the enclosed breaker could not be observed.

The load center at TX-564 appears to include circuits to the following;

o Two (2) duplex receptacles, noted to be connected to ground fault protected circuit at TX- 564 next to the kWh meter.

o One (1) single cord / plug type connector with flexible cable connected to the portable generator.

o Two (2) duplex receptacles, noted to be connected to ground fault protected circuit at the far-left side of TX-564 mounted on channel supporting a disconnect switch and welding receptacle.

At the left side of transformer TX-564 a 100 A disconnect switch and 480 Volt welding receptacle are mounted on channel with duplex on receptacles noted above mounted to the back of the

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1-5 westonandsampson.com same channel. The disconnect switch / welding receptacle appears to be connected to the 480 Volt secondary of TX-564 from a flexible cable extending out of the transformer enclosure.

The portable generator circuit breaker and combination disconnect, and power receptacle are mounted on channel on the transformer pad.

1.3.6 Existing Building 564 Portable Generator Operation and Transfer Arrangement

The following power system operation was reviewed with Wade Brillhart (Building Manager) and Mark Hall (Building Electrical Engineer) during Weston & Sampsons survey;

Loss of Normal Utility Power: Building personnel perform the following manual operations;

Turns off all MCC circuit breakers and starters.

Turn / change position of MTS to generator circuit.

Manually starts portable generator and ensures operation.

Generator supply / voltage is now present at MCC. Rotation and voltage is verified.

Manually turn back on only the following equipment fed from the MCC.

o Transformer T3 o Transformer T4 o Transformer T5 o Transformer T6 o PP-3

When generator supply / voltage is restored to the MCC, the following equipment automatically re-starts.

o AHU-1 o AHU-2 o EF-5 o EF-6 o P-1 o P-2

The Pumps Controlled from the PLC Enclosure are not turned back on and do not automatically re-start on generator operation.

o Pre-Process Pump o RLW Pump o PLW Pump o CPW Pump

The Sump Pump (15A circuit breaker) is controlled through rheostat control variable speed drive (VSD) and does not re-start automatically and is not manually restarted during generator operation.

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The facility manager recently indicated that the existing bridge crane may also be operated while connected to the existing portable generator, however, only to secure the load if the bridge crane is in use during a power outage. The bridge crane is manually re-started.

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2.0 PROPOSED NEW GENERATOR AND POWER SYSTEM

2.1 Description of the Proposed Power System

The general arrangement of the proposed and modified power system to accept a new permanent generator will be like the existing arrangement. The existing MTS located in Electrical Room 115 shall be disconnected and removed including associated feeders from the main switchboard and to the existing portable generator. A new 600 Amp automatic transfer switch (ATS) shall be installed in Electrical Room 115. The normal connection to the ATS shall be derived from the existing 600 Amp circuit breaker in the main switchboard presently feeding the existing MTS. The generator connection from the ATS shall extend to the new permanent generator through an outdoor enclosed circuit breaker at TX-564 concrete pad. The load connections of the ATS shall extend to the existing MCC.

Should the facility or building 564 lose normal power, the ATS shall automatically transfer from normal power to standby generator power. The ATS shall communicate a start command to the new permanent generator to automatically start and provide power through the ATS to the MCC.

2.1.1 Existing Portable Generator to Remain

The existing portable generator will remain as it will be needed for maintenance and repairs of the new permanent generator. The connections between the new permanent generator and the existing portable generator are planned to be based on the following general arrangement;

New permanent generator connection to an enclosed circuit breaker at / near the existing outdoor concrete pad for transformer TX-564.

The permanent generator enclosed circuit breaker shall be normally closed (N.C.) with key interlock.

Portable generator connection to new enclosed circuit breaker at / near the existing outdoor concrete pad for transformer TX-564.

The portable generator enclosed circuit breaker shall be normally open (N.O.) with key interlock to the permanent generator breaker, Manual key interlock between permanent generator circuit breaker and new portable generator breaker preventing both from being closed simultaneously.

Portable generator new connection box to directly accept and connect to flexible cable with separable connectors.

Single feeder connected between new ATS and the outdoor enclosed circuit breakers.

New ATS to include automatic / manual selector switch for operation of the ATS as an automatic transfer device or to be transferred manually.

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2.2 Removal and Replacement of Existing Equipment and New Equipment

2.2.1 Removal of Existing MTS and Associated Feeders

The existing manual transfer switch (MTS) shall be disconnected and removed from Electrical Room

115. The associated normal feeder wireway from the main switchboard to the MTS and the load feeder conduits from the MTS to the MCC shall also be disconnected and removed. The existing generator feeder conduit from the portable generator circuit breaker at the exterior concrete pad and to the MTS in Electrical Room 115 is routed below grade and below the building slab. The existing feeder consists of one (1) set of 4-inch conduit and is not large enough to accommodate the new feeder. Therefore, the MTS generator feeder conductors shall be disconnected and removed from the existing conduit and the conduit shall be abandoned in place, cut flush with the floor and the concrete pad and filled with non-shrinkable epoxy grout to prevent water entry.

2.2.2 Existing Transformer T2 and Panel RP-2

Existing 45 kVA transformer that feeds Panel RP-2 are presently fed from the existing Main Switchboard has been identified by NAVFAC and the facility manager that includes loads that need to be powered from the new permanent generator. Therefore, the feeder from the Main Switchboard will be transferred to and fed from the existing MCC. To accommodate this transfer in load, a spare starter in the MCC will be removed and replaced with a new circuit breaker with a new feeder extending from the new MCC breaker to feed the primary of transformer T2 on the second floor. The new cabling to T2 will be routed in the same fashion as the existing feeder between T2 and main SWBD as noted in dwg sheet 8.

2.2.3 Existing Transformer T6 and Disconnect Switch Replacement

Existing 5 kVA transformer T6 and two (2) disconnect switches; one for “CMCS 120 Volt Power” and the second for “Fire Alarm Pre-Action King Fisher Panels” are located immediately to the right next to the MCC. These items are required to be removed for the installation of the new ATS and the new ATS will be physically larger than the existing MTS and cannot be installed in the same location as the MTS for it will extend in front of the working space in front of the MCC and create an unsafe work condition and violate National Electrical Code work clearance requirements.

To minimize outage of the associated loads, a new 5 kVA transformer and disconnect switches will be installed in the location of the existing MTS. The existing circuits will be extended from the existing loads to the new equipment location and be done so in a phased approach and during planned outages to minimize disruptions.

2.2.4 New ATS and Associated Feeders

A new automatic transfer switch (ATS) is planned for installation in Electrical Room 115 to the immediate right of existing MCC where the existing transformer T6 and disconnect switches are presently installed however planned for replacement in a new location as described within.

The ATS will include new feeder conductors in new exposed conduit within Electrical Room 115 from the main switchboard to the normal power connections. The ATS load feeder conductors from the ATS to the MCC shall also be installed in new conduit within Electrical Room 115.

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The ATS generator feeder will be required to be installed between the ATS generator connections and the exterior generator via the enclosed circuit breaker planned for installation at the existing concrete pad at TX-564. The feeders will be routed from the ATS in Electrical Room 115 and extend through the corridor outside Electrical Room 115 to the rear of the building. The existing hung ceiling will be affected by the installation of the new feeder conduits. It is envisioned that the conduits will penetrate the exterior wall of the building near the rear corridor door and then be routed along the exterior of the building towards TX-564 concrete pad and then routed overhead above the walkway to the generator circuit breaker. The load side of the breaker shall then also be routed above the walkway to the building and continue along the building to the new permanent generator location. The overhead conduits above the walkway are planned to be installed a minimum of 10 feet above the finished walkway level supported at the building and at the concrete pad to prevent a walking obstruction. Based on site investigation surveys the area at TX-564 concrete pad and below the walkway includes multiple existing underground utilities that would prevent excavation and installation of new conduit below grade without extensive and costly utility relocations and repairs as well as affecting the operation of building 564.

2.3 New Permanent Generator

2.3.1 New Permanent Generator Location and Auxiliary Requirements

The new permanent generator is planned outdoors in the rear of building 564 in the area where existing building parking spaces are presently located. The outdoor generator will include a non-walk-in weather resistant enclosure with hinged lockable access panels. The enclosure will also include an electrical load center type panel to power auxiliary items such as jacket water heater, enclosure lighting and receptacles. The generator enclosure panel power source will be derived from an existing panel within the building in Electrical Room 115. The generator specifications will require a unit mounted circuit breaker and integral controller with alarms associated with generator condition and health. The controller will include a controller mounted emergency stop push button, a second emergency stop push button on the exterior of the generator enclosure and a third emergency stop push button planned for mounted on the building exterior wall.

2.3.2 New Permanent Generator Rating

The kW rating of the new permanent generator needs to be large enough to start and accommodate the connected load of the MCC that will be supported by the generator. Table 2-1 includes a summary of the MCC loads and the starting step / sequence used to determine the size of the new generator.

Previous design calculations performed through various manufacturer generator sizing software; the generator was planned to be 350 kW. However, NAVFAC and the facility manager has provided updated load information that includes the transfer of T2 and panel RP-2 from the Main Switchboard to the MCC to allow RP-2 to be powered from the new permanent generator system. Panel RP-2 is fed from transformer T2. Additionally, the facility manager indicated the existing bridge crane may need to be used during a utility source outage. These loads were not previously included in the generator calculations. Updated generator sizing calculations resulted in a 400 kW generator.

This is greater than the facility recorded load of the existing portable generator when operating, however the existing starting sequence of the load connected to the portable generator is performed manually, October 30, 2024

2-4 westonandsampson.com one load at a time and therefore the existing portable generator can be a lower rating. The new permanent generator will experience an immediate inrush current of all step 1 loads as noted in the table below due to the automatic transfer arrangement. Existing load that is not needed during emergency generator power will be modified by facility manager, owner or another designee to remain off.

Therefore, these were not included in the generator sizing calculations, or in the data table below.

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Table 2‐1 Generator Size Data

No

ID

Number

Equipment Identification

OCPD in MCC

Voltage (Volts)

Estimated Load

(Note 1)

Generator Starting Step

Notes

1 PP‐2 Lighting Power Panel 225 Amp ‐ 3 Pole Breaker 480 72.4 Amps Step 1 Note 2 2 PP‐3 Lighting Power Panel 225 Amp ‐ 3 Pole Breaker 480 163.7 Amps Step 1 Note 2

T‐2 / RP‐2

45 kVA XFRMR / Receptacle Panel

70 Amp ‐ 3 Pole Breaker

66.8 Amps

Step 1

Transferred from Main SWBD.

Spare starter to be replaced with feeder breaker.

4 T‐3 / RP‐3 45 kVA XFMR / Receptacle Panel

70 Amp ‐ 3 Pole Breaker 208 79.6 Amps Step 1 Note 3

5 T‐4 / RP‐4 45 kVA XFMR / Receptacle Panel 70 Amp ‐ 3 Pole Breaker 208 16.8 Amps Step 1 Note 3

T‐5 / LC

30 kVA XFMR / Power Panel

50 Amp ‐ 2 Pole Breaker

No load included in schedule.

Note 3.

T‐6 / FACP

5 kVA XFMR / FA System Panels

30 Amp ‐ 2 Pole Breaker

Minimal control panel load.

Note 3.

8 HWP P‐1 Hot Water Pump 20 Amp ‐ 3 Pole Breaker 480 3.7 HP Step 1 HWP P1 & HWP P2 are interlocked to prevent simultaneous operation.

HWP P‐2

Hot Water Pump

20 Amp ‐ 3 Pole Breaker

3.7 HP

10 AHU‐1 Air Handling Unit 25 Amp ‐ 3 Pole Breaker 480 7.5 HP Step 1 ‐‐‐

Bridge Crane

110 Amp ‐ 3 Pole Breaker

65 Amps

Step 2

No load value on drawing.

Manual operation after outage & transfer to generator.

Sump Pump

15 Amp ‐ 3 Pole Breaker

8 Amps

Not included on drawing.

No operation from generator.

20 ‐‐‐ Spare (Note 4) 3 Pole MCP Starter 480 ‐‐‐ ‐‐‐ ‐‐‐ 21 ‐‐‐ Spare (Note 4) 3 Pole MCP Starter 480 ‐‐‐ ‐‐‐ ‐‐‐

Notes:

Estimated load data is based on the data shown on Facility Drawings either on the one line diagram or within panel schedules. Current values are based on highest phase current shown in schedule.

2 Panel and lighting load values are calculated. Assume demand factor for generator sizing appplication.

3 Need to base load on transformer rating to account for transformer inrush current.

4 Starter ratings unknown. Spare starters were not shown on facility drawings.

Previously when the generator was rated at 350 kW, Weston & Sampson outlined the calculations to determine the rating of the new generator to NAVFAC project manager in an email and noted that due to starting requirements and inrush current associated with the motors and transformers that will occur during the automatic transfer to generator power, the calculations resulted in a 350 kW generator.

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Weston & Sampson further noted that after starting a generator of this size will only be loaded to approximately 50% of its rating and that loading to this level typically creates maintenance issues.

Weston & Sampson’s running load calculations results in similar values to the recorded 200 Amps +/-that was recorded by building operations and verbally provided. The present design of a 400 kW generator may exacerbate this issue and could require more frequent testing than previously believed.

In addition to maintenance issues with a lightly loaded generator, a 350 kW generator will require new conduits extending from the new ATS in the electrical room to the new generator and based on the underground utilities in the area, routing the new conduit below grade would not be feasible without significant utility relocations. In the correspondence to NAVFAC Weston & Sampson offered the following options for consideration as a possible design approach.

1. New Generator at 350 kW: Add the new generator at 350 kW and perform maintenance more often than typically required. It is difficult to determine how often maintenance would be required as it depends on operation and run time, however if not performed, could lead to failure to start manually or automatically.

2. Manual Transfer & Smaller Generator: Keep the existing manual transfer switch and connect to new permanent generator and transfer manually using the same procedure as presently using.

The new generator would be approximately 250 kW.

3. Modify Existing Motor Controls for Auto Transfer & Smaller Generator: Modify the existing controls through the CMCS / building control system to shut down the motors should the utility supply be lost, then restart the motors one at a time. This will require modifications to the control circuit, input from the new ATS that utility supply is lost and likely re-programming the CMCS / building control system. This will reduce the inrush from the motors after automatic transfer.

NAVFAC responded that the preferred approach is option 1 with a new 350 kW generator and is the basis of the design.

2.3.3 Main Switchboard Feeder Breaker to MCC and Inrush Current Review

In reviewing the ATS transfer operations planned to be performed automatically as noted within, Weston & Sampson reviewed the condition where the ATS automatically retransfers the MCC loads to the normal supply fed from the main switchboard, to verify that the Inrush current from the transformers and motors fed from the MCC would not inadvertently cause a trip of the switchboard feeder breaker to the MCC.

Based on Weston & Sampson’s review it appears that the switchboard feeder breaker will not trip due to inrush current upon re-transfer.

Figure 2-1 is a time current curve (TCC) showing a portion of the power system using the manufacturer nameplate information recorded during the survey. The single 125 kVA transformer is a summary of all transformers fed from the MCC to simulate the total transformer inrush possible.

Similarly, the single 100 HP motor is the sum of all motors fed from the MCC to simulate total motor starting current. As can be seen from the TCC, the switchboard feeder breaker is to the right of the

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2-7 westonandsampson.com transformer inrush point and to the right of the motor starting curve. Therefore, it is not expected that the breaker will trip from inrush current when re-transferred to the normal supply.

Figure 2-1: Switchboard Breaker TCC

2.4 Generator and New Exterior Equipment Grounding

The new permanent generator installed outdoors will include an electrical ground ring surrounding the generator with #4/0 bare copper cable and ground rod below grade in contact with the earth. As the new generator will be located close to building 564, the generator ground ring will also be connected to the existing building 564 counterpoise ground loop to match the connections of the building transformer

TX-564.

The new exterior electrical equipment located at the existing transformer pad will also be connected to earth ground, modify to include multiple ground rods as shown on detail 1, sheet E-903 Based on review of existing facility as-built drawings, there appears to be an existing counterpoise ground loop around existing transformer TX-564 presently installed below grade.

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The design approach includes exposing a portion of the existing ground loop and making a new ground connection to the loop to extend the loop to the new exterior electrical equipment installed at transformer TX-564 equipment pad.

2.5 New Permanent Generator - Controls and Annunciator(s)

2.5.1 Return of Normal Supply and ATS Operation

When normal power is lost to the building main switchboard or feeder to the MCC, the ATS will sense the loss of normal power, communicate a signal to start the permanent generator and automatically transfer from the normal supply to the generator. During this transfer period the load and equipment from the MCC will be momentarily de-energized and then re-energized after the generator is fully operating and the ATS transfer is complete.

When the normal utility-based supply returns, the ATS senses the return of voltage on the ATS normal power terminals. Typically, after a time delay that can be programmed in the ATS controls, the ATS will transfer back from the generator to the normal supply that also results in a momentary outage of the MCC loads during transfer. Then the ATS communicates a signal to the generator to begin a cooldown condition and shutdown.

It is planned that the ATS and associated features will return to normal supply automatically.

2.5.2 Permanent Generator and ATS Maintenance Operation

A permanent generator connected to a building power system and the ATS associated with the generator typically is programmed to perform a regular (usually monthly) automatic maintenance operation of starting the generator and the ATS transferring to generator to ensure the ATS, start signal and generator are functioning properly and can perform during a real power outage. The automatic maintenance operation is programmed through the ATS at a specific day of the month and time of the day. During the automatic maintenance operation, power is interrupted to the load as described above.

It is planned that the automatic maintenance operation will be programmed to be performed on a monthly basis at a preferred day and time. Generator testing will transfer load during off peak hours.

Note that Weston & Sampson does not recommend that generator and ATS maintenance verification operations be performed manually.

2.5.3 Generator and ATS Annunciators

As the generator is located outdoors in the rear of the building, and the noise from the generator when operating would be very difficult to hear to know the generator is operating, a small sized generator annunciator is planned for installation in the Facility Managers Office Room 117 in building 564 so that the facility operations can see on the annunciator that the generator is operating. The generator annunciator includes communications to the generator controller to report generator malfunction, alarms and operation.

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Similarly, the new ATS will also include a small annunciator with connection to the ATS to annunciate and report ATS alarms and position of the ATS in either in the normal position or the generator position.

The ATS annunciator will also be installed in the Facility Managers Office Room 117, adjacent to the generator annunciator. Depending on equipment manufacturers provided, the generator annunciator information and the ATS annunciator information can be included in a single common annunciator. This will be coordinated during construction based on the equipment submitted.

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3.0 ARCHITECTURAL

No architectural building design is believed to be required for the project however a new hung ceiling or ceiling repairs are expected in the first-floor corridor from Electrical Room 115 to the rear door for the installation of new electrical conduit. No architectural design has been performed at the time of publication, however, will be evaluated and addressed as part of the overall scope of work as the electrical design is closer to completion.

The new conduits required to be routed from the new ATS in Electrical Room 115 to the exterior generator and miscellaneous small electrical circuits required to interface with other exterior equipment is expected to be routed above the suspended ceiling in the interior building 564 corridor. The design documents include requirements for the contractor to remove and replace a limited portion of the existing ceiling for the installation of new electrical conduits. This is a common construction requirement often and typically successfully performed by the installation contractor without the need for a new ceiling. Weston & Sampson believes architectural design nor ceiling replacement is required and the notes on the design drawings provide proper direction and requirements.

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4.0 MECHANICAL

Mechanical design is not required. The new permanent generator will be specified and include an under-unit diesel fuel tank integral to the fabrication of the generator. Therefore, separate fuel pumps, mechanical piping and storage tank are not required.

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5.0 CIVIL / SITE

5.1 Excavation for New Generator

The installation of the new permanent outdoor generator will require excavation and concrete pad at the generator location. A structural detail was provided for the generator pad, and bollards are specified and shown to protect the generator from vehicular damage. The pad will be fit to the black top and there will be no additional civil work required.

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6.0 STRUCTURAL

6.1 New Generator Concrete Pad

The new generator will be installed on a concrete pad designed to support the weight of the generator and full fuel tank. The structural detail is included in the drawings and specifications. It shall be coordinated with manufacturer recommendations once a specific generator is ordered.

6.2 Exterior Building Conduit Supports

As described within, new feeder conduits are planned for installation and routing along the exterior of the building towards TX-564 concrete pad and then routed overhead above the walkway to the generator circuit breaker. The load side of the breaker shall then also be routed above the walkway to the building and continue along the building to the new permanent generator location. Facility personnel indicated that any support penetrations into the exterior building wall need to be reviewed by the facility due to integrity of the building wall in the classified area.

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7.0 ENVIRONMENTAL, PERMITS AND AUTHORIZATIONS

7.1 Environmental

The proposed Project includes the installation of a permanent standby generator to be located outdoors behind building 564 within the Naval Submarine Base. The scope of environmental impacts for the proposed Project will be performed by NAVFAC and is not included in Weston & Sampson scope of engineering services.

7.2 Permits and Authorizations by NAVFAC

The proposed Project includes the installation of a permeant standby generator to be located outdoors behind building 564 within the Naval Submarine Base. The scope of regulatory review and permitting for the proposed Project will be performed by NAVFAC and is not included in Weston & Sampson scope of engineering services.

Federal, state and local review and approvals may be required for generator emissions. It should be noted that although the generator will be standby and only operate for extended periods of time when the utility service, facility power system or building power feeder experiences a power outage, the new generator and associated controls will operate monthly to test the correct operation of the ATS, generator starting and generator capability to support the load. The generator will operate each month for a period of approximately 30 to 60 minutes.

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8.0 INDUSTRY STANDARDS AND REFERENCES

Relevant codes and standards include the following;

NFPA 70 – National Electrical Code, 2023 Edition.

NFPA 110 Testing and Service Requirements For Standby Power Systems

UL 1008 - UL Standard for Safety Transfer Switch Equipment

IEEE 81 - Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Ground System

NETA ATS - Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems

NEMA MG 1 - Motors and Generators

UFC – Unified Facility Criteria (USN)

B564 Generator Basis of Design Report-2024 11NOV24 REV Pages

Fillable_field:

SUBJECT: B564 Install Permanent Generator Final 100% Basis of Design Report, dated 30 October 2024

Document contains controlled unclassified information (CUI) Controlled by: Department of Navy Controlled by: NAVFAC-MIDLANT, NLON PWD and NAVSEA Naval Submarine Base New London CUI Categories:

a. Unclassified Controlled Nuclear Information – Defense (DCNI)

b. Critical Energy Infrastructure Information (CE-II) Limited Dissemination Control: Federal Employees and Contractors Only (FEDCON) POC: Cameron Levitre, NAVFAC, (860) 694-4572 Classification Guidance: https://www.archives.gov/cui