15-0608FinalRev-S Dayton VAMC Study Report.pdf

LOCATION:

Dayton VAMC 4100 West Third Street

Dayton, OH 45428

For:

Dayton VAMC 4100 West Third Street

Dayton, OH 45428

Reference: Contract No: VA250-15-C-0107 Project Name: Five year Arc Flash Review

Attention: Matthew D. Curtis/ Joy Amundson

SES Job No. 15-0608F2 Submitted By:

Manoj Shah PE

Sr. Compliance Engineer

Final Report Submittal date:

April 29th, 2016

Southwest Energy Systems, LLC

2231 E. Jones Ave., Phoenix, AZ 85040

Phone: 602-438-7500

Dayton Veterans Affairs Medical Center

Short Circuit, Protective Device Coordination and

Arc Flash Study.

(Final Submission)

Dayton VAMC-2016-Final

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TABLE OF CONTENTS

APPENDIX 1 :Guide to Interpreting Power Systems Analysis, Glossary & Reference

APPENDIX 2 Equipment Evaluation Summary

APPENDIX 3 Recommended Protective Device Settings

APPENDIX 4 Short Circuit Analysis Output

APPENDIX 5 Time-Current Coordination Curves

APPENDIX 6 Incident Energy Summary Table and Equipment Labels

APPENDIX 7 Voltage Drop Analysis

APPENDIX 8 Equipment Condition Table and Budgetary Estimate

APPENDIX 9 Generator Chart and NETA Maintenance Schedule

APPENDIX 10 Utility Data

APPENDIX 11 Single-line Diagrams

1.0 EXECUTIVE SUMMARY 1

1.1. Introduction 1

1.2. Findings 3

2.0 BASIS FOR ANALYSIS AND FINDINGS 13

2.1 Equipment Condition and Maintenance 13

2.2 Basis for Analysis and Component Naming 14

2.3 Short Circuit Analysis 15

2.4 Protective Device Coordination 17

2.5 Incident Energy (Arc Flash) Evaluation 19

2.6 Voltage Drop Analysis 23

2.7 Equipment Condition Evaluation 24

2.8 Generator and ATS Evaluation 24

3.0 FINDINGS AND RECOMMENDATIONS 25

3.1 Short Circuit Analysis 25

3.2 Coordination Study 28

3.3 Arc Flash Evaluation 35

3.4 Voltage Drop Analysis 35

3.5 Equipment Condition Evaluation 36

3.6 Code and General Discrepancies 36

3.5 Generator and ATS Evaluation 42-43

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1.0 EXECUTIVE SUMMARY

1.1. Introduction

Analysis of the majority of the power distribution system of the Dayton VA Medical Center facility in Dayton, Ohio (as per the configuration at the time of data collection, November 2015 to January 2016), was performed to determine the adequacy of the protection and equipment rating for the electrical power distribution system. The analysis performed included short circuit, protective device coordination studies and incident energy (Arc-Flash) evaluations.

1.1.1. Major objectives of the analysis are:

Compare the calculated fault duties with withstand and interrupting ratings for equipment in the scope of work.

Recommend settings for protective devices that will isolate faults in a manner that is consistent with the basic system design and operation. The recommendations given will balance system protection and selective fault isolation.

Identify incident energy levels and what level of personal protective equipment (PPE) is required for safe energized work.

Note areas of deficiency and make recommendations for corrective measures that are consistent with applicable codes and standards.

Provide a Percentage Voltage Drop Analysis on all buses and feeders in the scope of work.

1.1.2. The following buildings were not modelled due to ongoing construction at these buildings:

1.1.2.1.1. Building 302

1.1.2.1.2. Building 310

1.1.2.1.3. Building 411

1.1.3. The following buildings were not modelled in the arc flash analysis and implementation of the recommended settings due to ongoing construction at that building:

1.1.3.1.1. Building 330

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1.1.4. Various scenarios were modeled and the worst case incident energy of any scenario for each location was the one utilized for the arc flash hazard label for that location.

The following were the scenarios that were modeled and evaluated:

Scenerio#1: Recommended with Maximum Utility contribution, ATSs on Normal source, Utility Service from Tait and Crown with connecting 69 kV switch closed, and 12.47 kV Tie Breaker open.

Scenerio#2: Recommended with Maximum Utility contribution, ATSs on Normal source, Utility Service from Tait and Crown with connecting 69 kV switch open, and 12.47 kV Tie Breaker open.

Scenerio#3: Recommended with Maximum Utility contribution, ATSs on Normal source, Utility Service from only Crown with connecting 69 kV switch open, and 12.47 kV Tie Breaker closed.

Scenerio#4: Recommended with Maximum Utility contribution, ATSs on Normal source, Utility Service from only Tait with connecting 69 kV switch open, and 12.47 kV Tie Breaker closed.

Scenerio#5: Worst case with 12.47 kV sources changed over as per 3 year schedule

Scenerio#6: Recommended and all ATS’s on Alternate (Generator) sources.

1.1.5. Full narratives of the analysis performed as well as the findings and recommendations of the analysis are included in Sections 2 and 3 of this report.

The appendices include the computer output from the analysis performed and tables containing the recommended settings for the adjustable devices in the scope of work. Time current curves, and one-line diagrams of the system model are also included in the appendices.

1.1.6. The software system used for this analysis was SKM Systems Analysis, Inc.

PowerTools for Windows analysis suite (PTW).

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1.2. Findings

1.2.1. Short Circuit Analysis

1.2.1.1. There are twenty-seven (27) locations where the available fault current exceeds the self-protected rating for the equipment. Series combination rating cannot be applied here. Refer to Section 3.1 for more details.

1) Building 115:

a) Control Panel 115 CH-1 CP

b) Panel 115-1-03A-2B

c) Panel 115-1-03A-2D

d) Panel 115-1-03A-2E

2) Building 128:

a) Panel 128 Emergency

b) Panel 128 Pnl 1-03

c) SWBD 128-1

d) Panel 128Mach Shop

3) Building 143:

a) Panel 143-1-1-1A

4) Building 305:

a) Panel 305-1-06

b) Panel 305-1-08A

c) Panel 305CH-2

5) Building 307:

a) Panel Pnl-1A

b) Panel Pnl-1B

c) Panel Pnl-1C

d) Panel Pnl-1D

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e) Panel Pnl-GA

f) Panel Pnl-GB

g) Panel Pnl-GC

6) Building 315:

a) Control Panel 315 CH-1 CP

7) Building 320:

a) SWBD 320E-1

8) Building 330:

a) Panel HNBD3 (US1C distribution).

9) Building 402:

a) SWBD 402 MDP-1

10) Building 408:

a) Panel 408-1-08

11) Building 410:

a) Panel 410-1-04

b) Panel 410-1-04-21

c) Panel 410E-1-5

1.2.1.2. All other equipment analyzed were found to have acceptable self or series protected ratings.

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1.2.2. Protective Device Coordination

1.2.2.1. There are a few locations listed below where there is lack of selectivity.

Refer to section 3.2 and Appendix 5 (TCCs) for more details.

1) Building 108:

a) TCC#1: Building 108-Panel DP-1

2) Building 118:

a) TCC#5 and #6: Building 118:

3) Building 126:

a) TCC#11: Building 126-126-1-10.

4) Building 128:

a) TCC#21: Building 128-ATS-128

b) TCC#23: Building 128-Panel 01A-04

5) Building 135:

a) TCC#41: Building 135-Panel 135-1-1.

b) TCC#42: Building 135-Panel 135-1.

c) TCC#45: Building 135-Panel 135-03A-02.

6) Building 147:

a) TCC#52 and 57: Building 147-147E-1.

b) TCC#59: Building 147-Panel 147E-1-05-01B-01.

c) TCC#61: Building 147-Panel 147E-1-06-3C.

7) Building 305:

a) TCC#66: Building 305-Panel 305-1-02A.

b) TCC#69: Building 305-Panel 305-1-04A.

c) TCC#71: Building 305-Panel 305-1-05.

d) TCC#77: Building 305-Panel 305-1-09A.

e) TCC#79: Building 305-Panel 305-1A.

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8) Building 307:

a) TCC#82: Building 307-Panel 2F.

b) TCC#83: Building 307-Panel GB

9) Building 320:

a) TCC#110: Building 320-MCP-A/T-A.

10) Building 330:

a) TCC#173: Building 330-US1A-ATS#9.

b) TCC#226, 228: Building 330-US1B-Panel EDP2.

c) TCC#229: Building 330-US1B-Panel HC1A.

d) TCC#231: Building 330-US1B-Panel HC2A.

e) TCC#232: Building 330-US1B-Panel HC3A.

f) TCC#246: Building 330-US1B-Panel HEBB.

g) TCC#281: Building 330-US1C-Panel HN1D.

h) TCC#284: Building 330-US1C-Panel HN3D.

i) TCC#286: Building 330-US1C-Panel HN4B.

j) TCC#287: Building 330-US1C-Panel HN5B.

k) TCC#288: Building 330-US1C-Panel HN6B.

l) TCC#290: Building 330-US1C-Panel HN7B.

m) TCC#291: Building 330-US1C-Panel HN8B.

n) TCC#292: Building 330-US1C-Panel HN9B.

o) TCC#293: Building 330-US1C-Panel HNBB.

p) TCC#318: Building 330-US1D-Panel HN1A.

q) TCC#320: Building 330-US1D-Panel HN1E.

r) TCC#332: Building 330-US1D-Panel HN5C.

s) TCC#334: Building 330-US1D-Panel HN6C.

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t) TCC#336: Building 330-US1D-Panel HN7, 8, 9A.

u) TCC#337: Building 330-US1D-Panel HN7A.

v) TCC#338: Building 330-US1D-Panel HN7C.

w) TCC#339: Building 330-US1D-Panel HN8A.

x) TCC#340: Building 330-US1D-Panel HN8A.

y) TCC#341: Building 330-US1D-Panel HN9A.

z) TCC#342: Building 330-US1D-Panel HN9C.

aa) TCC#346: Building 330-US1D-Panel HNBC.

bb) TCC#348: Building 330-US1D-Panel HNBE.

cc) TCC#349: Building 330-US1D-Panel HNP.

11) Building 400:

a) TCC#430: Building 400-400-1-02A.

b) TCC#431: Building 400-400-1-03.

c) TCC#435: Building 400-400-1-08.

d) TCC#437: Building 400-400-1-11A.

12) Building 401:

a) TCC#448: Building 401-Panel 401-1.

13) Building 408:

a) TCC#461: Building 408-Panel 408-1-03.

b) TCC#462: Building 408-Panel 408-1-03-02A.

c) TCC#463: Building 408-Panel 408-1-04.

d) TCC#465: Building 408-Panel 408-1-07.

e) TCC#466: Building 408-Panel 408-1-10A.

14) Building 409:

a) TCC#479: Building 409-409E-1-01.

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15) Building 410:

a) TCC#506: Building 410-410E-03

b) TCC#508: Building 410-Panel 410E-04.

c) TCC#510: Building 410-Panel 410E-07.

d) TCC#511: Building 410-Panel 410E-08.

Except in cases where selectivity is unattainable, the recommended protective device settings (See Appendix 3) in this report will provide adequate system protection and coordination for the rest of the system.

1.2.3. Arc Flash Evaluation

1.2.3.1. Some of the locations studied were found to have incident energy levels that exceed 40 cal/cm2 (no safe level of PPE recommended). In locations where no recommended safe level of PPE exists, either energized work should be prohibited or extension tools (eg. hotstick) should be used to distance personnel from the potential arc point. The incident energy at the working distance dictates the required PPE.

Wherever possible, protective device settings have been changed to try to reduce the incident energy levels. Please refer to Sections 3.3 and

4.3 for more detailed information.

1.2.3.2. The incident energy calculations assume the utility data and as per data provided by the client as well as data collected by us. The incident energy calculations also assume the recommended settings in Appendix 3 are implemented. These settings must be implemented for the data provided on the recommended labels to be correct. Improper or inadequate maintenance can result in increased opening time of the overcurrent protective device, thus increasing the incident energy.

1.2.4. Voltage Drop Analysis

1.2.4.1. Some of the locations (bus and feeders) studied were found to have levels that exceed the requirements in NEC article 210.19(A) fpn#4 (5% allowable percentage voltage drop for combination of both feeder and branch circuits). Please refer to Sections 3.5 and Appendix 7 for more detailed information.

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1.2.5. Equipment Condition Evaluation

1.2.5.1. Some of the equipment inspected were found to be in bad condition (Grade D or F). The equipment have been assigned an equipment condition rating. Please refer to Sections 3.5 and Appendix 8 for more detailed information.

1.2.6. Code and General Discrepancies

1.2.6.1. There are a few locations listed below where there are code violations and general discrepancies. Refer to section 3.6 for more details.

1) Building 118:

a) TX-T-4-1 is a 50 kVA transformer (12470-240V, single phase). Secondary current is 208A. Secondary breaker has to be <1.25x (Max 300A). Present secondary breaker is 600A. (Ref NEC Table 450.3(A)).

2) Building 120:

a) The feeder tap conductors (AWG#6) from 100A CB-120- 1-1 at Panelboard 120-1 feeding 120-1-01F Disconnect, 120-1-01A-01-01B, 120-1-01A-01-01C, 120-1-01A-01- 01D, and 120-1-01A-01-01E (AWG#6) are not properly protected as per their ampacity of 65A (protected by upstream 100A circuit breaker).

3) Building 126:

a) The conductors (AWG#4) from 100A CB-126-1-08A-05 at Panelboard 126-1-08A feeding panel 126-1-08A-05 are not properly protected as per their ampacity of 85A (protected by upstream 100A circuit breaker).

b) The conductors (AWG#4) from 100A CB-126-1-11 at Panelboard 126-1 feeding panel 126-1-11 are not properly protected as per their ampacity of 85A (protected by upstream 100A circuit breaker).

4) Building 143:

a) Panel 143-1-08-14 should be relabeled 143-1-2A-39.

5) Building 305:

a) The conductors (AWG#8) from 100A CB-305-1-04-34A/B at Panelboard 305-1-05-04 feeding panels 305-1-04-

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34A/B are not properly protected as per their ampacity of 50A (protected by upstream 100A circuit breaker).

b) The conductors (AWG#8) from 70A CB-305-1-05-10 at Panelboard 305-1-05 feeding panel 305-1-05-10 are not properly protected as per their ampacity of 50A (protected by upstream 70A circuit breaker).

c) The conductors (AWG#8) from 70A CB-305-1-10 at Panelboard 305-1 feeding panel 305-1-10 are not properly protected as per their ampacity of 50A (protected by upstream 70A circuit breaker).

d) Panel 305-05-9A is mislabeled 305-05-10A.

e) Panel 305-05-9B is mislabeled 305-05-10B.

f) Panel 305-1-03, working clearance violation.

6) Building 307:

a) There is insufficient working space at the rear of the main 208Y/120Volts, 1600A 307-1 switchboard. There is a plywood partition at the rear which provides only 18” of working space. Working space needs to be at least 36”.

b) The line side tap of the main for panel EM voids the listing of the switchboard and the tap conductor has to be at least AWG#2/0 (present AWG#6). (Reference NEC article 240.21).

7) Building 315:

a) At 480Y/208V, 1200A Switchboard Bldg 315 (Panel MD), no ground fault protection is provided as required by NEC article 215.10. Also an additional level of ground fault protection on all feeders as required by NEC article 517.17 should be provided and be selectively coordinated with the main ground fault protection.

b) At panel EM, some spacers are missing

c) There is insufficient working space at the front of SWBD ATS as Panel LSD is in front of it within 18”. Working space needs to be at least 42”.

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8) Building 320:

a) At Switchboard Bldg 320, only one feeder breaker (CB- 320ATS-CR-N) has ground fault protection. For additional level of ground fault protection as required by NEC article 517.17, all feeders should be provided with ground fault protection and be selectively coordinated with the main ground fault protection

9) Building 321:

a) The conductors (AWG#3/0) from 225A CB-Bldg 321 Main feeding primary of 150 kVA transformer TX-T321 are not properly protected as per their ampacity of 200A (protected by upstream 225A circuit breaker).

10) Building 330:

a) PET location: The conductors (AWG#8, 50A) feeding primary of 45 kVA transformer TX-LN-1B PET are protected by a 25A circuit breaker at Panel HN-1B-PET.

This may cause nuisance tripping on transformer inrush.

b) The conductors (AWG#2) from 150A CBs for Elevators at Panelboard EL1 are not properly protected as per their ampacity of 115A (protected by upstream 150A circuit breakers).

c) The conductors (AWG#2) from 150A CBs for Elevators at Panelboard EL2 are not properly protected as per their ampacity of 115A (protected by upstream 150A circuit breakers).

d) There is insufficient working space in front of electrical panels at room 1B-135. Working space needs to be at least 36”.

e) 12.47kV-480Y/208V 2000kVA transformer TX-USA is protected by 100A fuses on the primary. It is recommended to replace these with 125A ones. (This is also called for in the schematics that were provided).

f) Panel LNBC is a 60A panel with a 100A main.

g) Panel LN4C is a 60A panel with a 100A main.

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11) Building 400:

a) Provide proper overcurrent protection for Air Conditioning transformer primary at panel 400-1-03-01A.

12) Building 401:

a) The conductors (AWG#2) from 401-1-04-01B (L3A) at Panelboard 401-1-04-01A (L2A) feeding 401-1-04-01B (L3A) are not properly protected as per their ampacity of 115A (protected by upstream 225A circuit breaker).

13) Building 409:

a) Panel 409E-1-07 is a 50A panel with a 100A main.

Violation of NEC article 408.36 (Panelboard shall be protected by overcurrent protective device (OCPD) rated not greater than rating of panelboard).

b) Bus plug 409E-1B-16E-01B is installed above drop ceiling.

Violation of NEC article 110.26 (Working space clearance).

14) Building 410:

a) The tap conductors (AWG#2/0) to Fuse switch FS410-1- 06 are not properly protected as per their ampacity of 175A (protected by 400A upstream circuit breaker). The conductors (AWG#3/0) from Fuse switch FS410-1-06 are not properly protected as per their ampacity of 200A (protected by 400A upstream fuse).

b) The conductors (AWG#2) from 225A CB-410-1-5A at Panelboard 410-1 feeding panel 410-1-5A are not properly protected as per their ampacity of 115A (protected by upstream 225A circuit breaker).

c) The tap conductors (AWG#2/0) at Panelboard 410-1-04 feeding panel 410-1-04-01 are not properly protected as per their ampacity of 175A (protected by upstream 400A circuit breaker).

d) 200A Fuse at FS 410E-1-02A-01A is a class H NON type fuse. Recommend replace with a class RK1 fuse.

e) Panel 410E-1-04 is a 100A panel fed from a 225A circuit breaker. Violation of NEC article 408.36 (Panelboard shall

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be protected by overcurrent protective device (OCPD) rated not greater than rating of panelboard).

15) Building 412:

a) The tap conductors (AWG#4) at Panelboard 410-1-04A feeding panel 410-1-04B are not properly protected as per their ampacity of 85A (protected by upstream 100A circuit breaker).

16) General:

Although may be temporary, some electrical rooms were noticed to be used as storage rooms, especially by other trades. Space around electrical equipment shall be kept clear.

1.2.7. Generator and ATS Evaluation

1.2.7.1. Some of the generators were found to have older generation controllers (governor, automatic voltage regulators etc). Some generators had the neutral bonded to ground even when not a separately derived system.

Please refer to Sections 3.7 and Appendix 9 for more detailed information.

2.0 BASIS FOR ANALYSIS AND FINDINGS

2.1 Equipment Condition and Maintenance

In order to protect personnel and assure safe operations, electrical equipment must be in proper working condition. This is assured with an ongoing routine maintenance inspection and testing program. Enclosures must be intact and complete to function as designed by the manufacturer. This includes verifying that all screws and bolts are in place and tight. NFPA 70E has the following mandates.

205.2 General Maintenance Requirements. Electrical equipment shall be maintained in accordance with manufacturers’ instructions or industry consensus standards to reduce the risk of failure and the subsequent exposure of employees to electrical hazards.

205.4 Overcurrent Protective Devices. Overcurrent protective devices shall be maintained in accordance with the manufacturers’ instructions or industry consensus standards.

Maintenance, tests, and inspections shall be documented.

The NEC has further requirements.

110.26 Spaces About Electrical Equipment. Access and working space shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.

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Equipment that has been modified to not be consistent with the original equipment listing, is deteriorated, or does not function as designed by the manufacturer will invalidate the results of this study and may result in injury or death.

The InterNational Electrical Testing Association (NETA) has established recommended minimum intervals for testing based on the condition of the equipment and reliability requirement of the facility (NETA Maintenance Testing Standard, Appendix B). Generally this falls into a 3 to 5 year cycle for most testing, but can be significantly higher for certain tests and inspections for critical facilities.

2.2 Basis for Analysis and Component Naming

Electrical system data for the analysis performed was data collected by Southwest Energy Systems (SWES) as well as per the one-lines provided by the client.

Utility data was based on data provided by Dayton Power and Light Co, attached at Appendix 10.

The SKM analysis suite was used for all analysis performed. Using this software, a computer model of the electrical system was created based on data obtained for the analysis.

The single line diagrams in Appendix 11 is a graphical representation of the computer model that was used for the analysis. The components on the single line include data blocks of transformer sizes and impedances, cable sizes and length, and protective device data (manufacturer, type, and ratings). Each component on the single line diagram is identified by a unique label that corresponds to the type of equipment and the equipment served by that device.

For example a component identified as “CB T1” is a circuit breaker (CB) that serves T1. Common identifiers are used in this report are as follows.

CB - Circuit Breaker DS - Fused Switch F - Feeder (Conductor or Bus Duct) XF - Transformer (When not uniquely named) MAIN - Main Device GFR - Ground Fault Relay

For components that serve automatic transfer switches, a suffix is added to identify the normal (N) or emergency (E) source.

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2.3 Short Circuit Analysis

Based on the model created, an analysis of the system was performed to determine the maximum fault levels at the switchgear and panels covered within the scope of work.

The PTW A_FAULT module used for the analysis uses the ANSI/IEEE C37.13 standard for calculation of fault currents. This analysis differs from a classical short circuit calculation in that it addresses the initial fault current that is asymmetrical and has a DC offset (See the figure below). The initial current asymmetry can last several cycles and is seen by the short time and instantaneous trip components in circuit breakers.

Figure 1: Fault Current Asymmetrical Decay

The A_Fault module calculates crest current values and interrupting ratings required for the proper selection of power circuit breakers, insulated and molded case breakers, and fuses.

Crest current used to evaluate the interrupting rating of low voltage breakers.

These values are based on the ANSI (NEMA) specified test power factor for these breakers as shown below:

Table 1: Test Power Factor and Asymmetry Factor

Protective Device Test PF

(%) Test X/R Tested Asymmetrical withstand Capability

LV Fuse 15 6.6 1.62

LV Power Circuit Breaker 15 6.6 1.62

Molded Case Circuit Breaker (AIC >20kA) 20 4.9 1.53

Molded Case Circuit Breaker (AIC 10-20kA) 30 3.2 1.38

Molded Case Circuit Breaker (AIC =10kA) 50 1.7 1.15

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The asymmetrical current is calculated as follows.

R X rmssymmcycleasymrms eII

2/1 21

(1)

This value should not exceed the equipment rating times the appropriate test factor for the device.

If the calculated X/R ratio is greater than the test X/R ratio, then there is an additional symmetrical factor that must be evaluated as well. The symmetrical rating is calculated as follows:

testR X systemR X rmssymmsymmLVF e e

II

(2)

When evaluating the interrupting capability of low voltage protective devices two ratings can be used, self-protected or series combination.

Self-protected ratings are the labeled ratings from the manufacturer for the equipment. If the fault currents seen by the protective devices exceed the self-protected ratings it may result in failure during operation. Equipment failure is explosive in nature and can cause injury or death to personnel and will severely damage equipment resulting in a prolonged equipment outage.

Series combination ratings are an alternative to self-protected ratings. Where fault levels that exceed the rating of a device, one or more devices upstream operate simultaneously and limit the current to a level below the self-protected rating of the device. The series rating applied is only valid for tested combinations of devices. Peak let-though of current-limiting devices is not acceptable for use with molded case circuit breakers since their operation creates a dynamic impedance that can limit the current seen by upstream devices below their current limiting range. When series ratings are used, the National Electrical Code (NEC), Section 110-22, requires that equipment be field marked to indicate the equipment has been applied with a series combination rating. This marking must be legible to personnel who work on the equipment.

Medium voltage equipment evaluation has two components: momentary and interrupting ratings. The momentary rating is the asymmetrical current seen ½ cycle after the fault occurs. The interrupting rating reflects the fault duties at the time when a protective device will operate to clear a fault (typically 2, 3, 5 or 8 cycles).

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ANSI allows a simplified momentary rating calculation of 1.6 times the symmetrical fault duty. The actual value is calculated as follows:

c

R X symmrmsmsmomentaryr eII

(3) where c is ½ cycle

The Equipment Evaluation Table in Appendix 2 summarizes the fault duties and compares the calculated fault duties (with appropriate ANSI multiplying factors) with the equipment ratings for each location within the system modeled.

Full output of the input data and short circuit results are included in Appendix

4. The output contains the fault duties for three-phase, single-line to ground, line-to-line, and double-line to ground faults. Also included is the average three-phase asymmetrical and RMS current at one half cycle.

2.4 Protective Device Coordination

Protective Device Coordination analysis was performed by plotting the protective device time-current characteristics of the equipment in the scope of work on to a series of Time-Current Characteristic (TCC) curve sets. The SKM coordination module was used for all analysis in this report. The TCC are log-log graphs shown with the device operating time versus current. These TCC curves illustrate graphically the quality of protection and coordination provided by the protective devices.

Starting with the device nearest the source, the TCC’s are plotted with the objective of maintaining an adequate coordination interval between devices in series. In the analysis performed, adequate time coordination interval is defined as follows:

Low Voltage Circuit Breakers: The tolerance bands for the devices do not overlap.

Fuses: The maximum clearing time for the protected device is no more than 75% of the minimum melting time for the protecting fuse.

Relays: The operating time for the protecting device is longer than the sum of operate time for the protected device, the breaker opening time for the protected device, a relay tolerance, and other relay functions (i.e.

breaker failure). Typically a time interval of 0.2-0.3 seconds for electro-mechanical relays was used if breaker failure was not present (0.3-0.4 seconds with breaker failure protection). Newer solid-state and microprocessor based relays are much more accurate and can have intervals as low as 0.15 seconds.

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ANSI/IEEE Standard 242 states, "Whether minimizing the risk of equipment damage or preserving service continuity is the more important objective depends on the operating philosophy of the particular plant or business." The recommended settings presented in this report offer a compromise between coordination, protection, and service continuity. Changes in system operation may require re-evaluation of device settings to allow for selective operation.

There are occasions where selective operation cannot be achieved but is considered acceptable. These primarily occur when the devices are not adjustable (or have limited adjustments) and where there are a large number of devices are in series.

Devices are considered to be in series if operation of either device results in the same equipment be de-energized, such as a feeder breaker in one panel serving a main breaker in downstream panel (only one). If the downstream panel does not have a main breaker, then the feeder breaker in supplying panel cannot be considered directly in series with the feeder breakers in the downstream panel (because there are more than one). The findings and recommendation that follow in Section 3 do not address the lack of selectivity due to devices directly in series.

When the available fault current results in the operation of two or more instantaneous trip devices that are not directly in series, there will be a lack of selectivity. This is shown graphically on the TCC curves sets when the curves overlapping in the 0.1 second or less area. The lack of selectivity due to instantaneous units in series is very common and is not usually a problem, since the most faults involve a resistance to ground and thus are smaller in magnitude. The finds and recommendation that follow in Section 3 do not address the lack of selectivity due to instantaneous units in series.

Ground fault protective devices are typically only on specific devices (primary switchgear main and sometimes feeders). Selectivity is different from phase fault protection since ground fault devices do not have to (and typically cannot

be) set above the load level. Separate TCC curves sets are generated when there are more than one level of ground fault devices in a system.

A curve set consists of the time current characteristic curves (TCC’s) of devices plotted on a log-log graph in current vs. time. The first step in the analysis is to determine the voltage, current scale, drawing name, and description. These are indicated in the title block area of the curve set.

Time-Current Curve (TCC) sets for the systems analyzed are in Appendix 5.

The curve set contains a simplified single-line diagram that graphically shows the relationship between the devices plotted on each curve set. The voltage and current scale multiplier used are included in the title block area of the curve set. The curves for each device are terminated at the maximum fault magnitude available at the device's location.

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2.5 Incident Energy (Arc Flash) Evaluation

The majority of electrical injuries (as much as 80%) are burns and blast damage that are the result from exposure to the energy and debris liberated during an arcing fault. The burns are typically second and third degree. Impact and pressure injuries and result in serious damage to bones and internal organs.

All too often, these injuries are fatal.

Incident energy evaluations are used to determine the required level of personal protective equipment (PPE) or whether it is prohibited to work on the equipment energized (incident energy above 40 cal/cm2). This information must be incorporated in the site safety manual to provide personnel with the information required by NFPA and OSHA standards. The relevant standards can be summarized as follows:

The NEC (NFPA 70-2014) requires equipment to be field marked to indicate where a flash hazard exists.

110-16: Arc-Flash Hazard Warning: Electrical equipment such as switchboards, panelboards, industrial control panels, meter socket enclosures, and motor control centers that are in other than dwelling units and are likely to require examination, adjustment, servicing, or maintenance while energized shall be field marked to warn qualified persons of potential electric arc flash hazards. The marking shall be located so as to be clearly visible to qualified persons before examination, adjustment, servicing, or maintenance of the equipment.

NFPA 70E-2015, Standard for Electrical Safety in the Workplace, states that “When an employee is working within the restricted approach boundary, the worker shall wear PPE in accordance with 130.4. When an employee is working within the arc flash boundary, he or she shall wear protective clothing and other PPE in accordance with 130.5. All parts of the body inside the arc flash boundary shall be protected.”

OSHA regulations represent the other major source of standards that apply to arc flash hazards. The primary regulations are in 29CFR 1910 Subparts I, and S. These can be broken down into three general areas, hazard identification and PPE selection, training, and proficiency.

1910.132(d) Hazard assessment and equipment selection.

The employer shall assess the workplace to determine if hazards are present, or are likely to be present, which necessitate the use of personal protective equipment (PPE). If such hazards are present, or likely to be present, the employer shall: Select, and have each affected employee use, the types of PPE that will protect the affected employee from the hazards identified in the hazard assessment; Communicate selection decisions to each affected employee; and, Select PPE that properly fits each affected employee.

The employer shall verify that the required workplace hazard assessment has been performed through a written certification that identifies the workplace evaluated; the person certifying that the evaluation has been performed; the date(s) of the hazard assessment; and, which identifies the document as a certification of hazard assessment.

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1910.335(a)(1)(i) Personal Protective Equipment

Employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed.

1910.132(f) Training.

The employer shall provide training to each employee who is required by this section to use PPE. Each such employee shall be trained to know at least the following: When PPE is necessary; what PPE is necessary; How to properly don, doff, adjust, and wear PPE; The limitations of the PPE; and, the proper care, maintenance, useful life and disposal of the PPE.

Each affected employee shall demonstrate an understanding of the training specified in paragraph (f)(1) of this section, and the ability to use PPE properly, before being allowed to perform work requiring the use of PPE.

1910.132(f)(3) Proficiency & Retraining

When the employer has reason to believe that any affected employee who has already been trained does not have the understanding and skill required by paragraph (f)(2) of this section, the employer shall retrain each such employee. Circumstances where retraining is required include, but are not limited to, situations where: Changes in the workplace render previous training obsolete; or Changes in the types of PPE to be used render previous training obsolete;

or Inadequacies in an affected employee's knowledge or use of assigned PPE indicate that the employee has not retained the requisite understanding or skill.

The employer shall verify that each affected employee has received and understood the required training through a written certification that contains the name of each employee trained, the date(s) of training, and that identifies the subject of the certification.

The calculations used in this study meets or exceeds the NEC and NFPA 70E requirements. A table summarizing the results for all locations evaluated and data labels for each location reviewed is included in Appendix 6.

2.5.1 Analysis Methods

The Arc Flash module used for this analysis incorporates results from the short circuit and coordination analysis to yield the arcing fault duties at locations where arc flash evaluations are to be performed and the clearing time for the protective device nearest the location.

IEEE Std 1584-2002 and amendment IEEE Std 1584b-2011 IEEE Guide for Performing Arc-Flash Hazard Calculations contains calculation methods developed through testing by several sources to determine flash boundary distances for unprotected personnel and the incident energy at the working distance for qualified personnel working on energized equipment. The incident energy level can be used to determine the proper PPE required for personnel.

The equations developed in the IEEE standard assess the arc flash hazard based on the available (bolted) fault current, voltage, clearing time, equipment type, grounding, and working distance.

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In locations where no safe level of PPE exists, either energized work should be prohibited or extension tools (i.e.: hotstick) should used to distance personnel from the potential arc point. The incident energy at the working distance dictates the required PPE.

The incident energy calculations performed are based on the system configuration shown in the one-lines in Appendix 11 and settings shown in Appendix 3. Changes in the system configuration, operating mode, equipment settings, or the utility source equipment may result in changes that require recalculation of the incident energy results.

The incident energy calculations performed for equipment with a main protective device are based on a line side fault on the main protective device unless the main is isolated from the feeder sections, in which case the incident energy calculations are performed based on the operation of the main for these downstream sections.

2.5.2 PPE Description

Depending upon the incident energy levels present at a location, different levels of PPE are required for safe work. The following information is based on PPE descriptions included in the NFPA 70E- 2015 Annex H Table H.3 (b). Where site specific PPE descriptions and ATPV information is not available, the data in this table is used for the evaluation. The color code in the last column of the table is used to identify the background color on the equipment labels.

While not specifically noted in the standard, a maximum incident energy above which energized work is prohibited is a prudent safety measure.

This is a site specific determination, but would typically be limited to the arc rating of the highest available PPE (typically this is 40 cal/cm2), but can be higher or lower depending the determination of the site safety manager. In the absence of specific site safety information an upper limit of 40 cal/cm2 will be used.

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Table 2: Personal Protective Equipment Categories

INCIDENT

ENERGY

(cal/cm2)

CLOTHING DESCRIPTION

COLOR

CODE

<1.2 Non-melting or untreated natural fiber long-sleeve shirt, long pants or coveralls, safety glasses or goggles, hard hat with face shield, hearing protection, leather glove protectors.

1.2-12

AR long-sleeve shirt with AR pants or AR coveralls (rated equal to or greater than the determined incident energy), hearing protection, arc-rated hard hat with arc-rated face shield and balaclava, safety glasses or goggles, leather glove protectors, leather work boots.

>12

AR long-sleeve shirt with AR pants or AR coveralls or arc flash suit with arc-rated arc flash suit hood with hard had (rated equal to or greater than the determined incident energy), hearing protection, safety glasses or goggles, arc-rated leather glove protectors, leather work boots.

>40*

INCIDENT ENERGIES AT THIS LOCATION EXCEEDS MAXIMUM

SAFE WORKING LEVEL. ENERGIZED WORK IS NOT

RECOMMENDED

*The maximum incident energy for safe work is a site specific determination.

AR= Arc rated

2.5.3 Arc-Flash Labels

Based on the results of the study, labels were printed that detail the incident energy and shock protection requirements for each location studied when exposed energized work is performed. The labels detail the incident energy, flash protection boundary, PPE requirements, Glove rating, and the approach distances.

Locations where the voltage is 240V or below that are served by a transformer smaller than 125kVA are considered to have incident energy levels less than 1.2 cal/cm2 by standard and do not require detailed calculations. Labels are prepared for these locations with the same information at the calculated locations except the incident energy is identified as <1.2 cal/cm2 and the flash boundary is identified as <18 inches.

The labels are color coded based on the incident energy labels as shown in Table 2 and ANSI Z535.4 standards. Locations that do no require arc-rated PPE have yellow caution banners. Locations where arc-rated PPE is required have orange warning banners. Locations where the incident energy exceeds maximum incident energy for the site are prohibited locations for energized work and have red danger banners.

For studies with multiple modes of operation (such as transferable loads served by emergency generators via transfer switches), the calculated incident energy will be different based on the calculated fault currents

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and associated clearing time of protective devices for each mode. The worst case incident energies are used for the labels unless the incident energies go from a workable to prohibited location. These locations have two labels printed with identification as to mode of operation on each label. Samples of typical labels are shown below (actual label size is 4” x 5”).

2.6 Voltage Drop Analysis

2.6.1 The NEC recommends a limit on the total voltage drop in any one branch or the total bus voltage drop. Thus, it is critical in the design process to know the voltage drop in each branch of the power system, and the total voltage drop from the source of supply to the bus in the branch circuit.

The voltage drop calculations are incorporated directly into the calculation of the steady-state load flows.

More simply, adding the receiving end voltage at each load bus and the branch voltage drop is equal to the sending end voltage, as illustrated:

The sending end voltage may be expressed as:

Vs=Vr+I(R+jX)

Where:

Vs sending bus voltage;

Vr receiving bus voltage;

I load current;

R feeder resistance;

jX feeder reactance.

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The software reports the magnitude difference between the receiving and sending end voltages as the voltage drop, expressed on a three-phase (line-to-line) basis.

2.6.2 The database for the voltage drop analysis is the same as that is used for the short-circuit analysis. Estimated loads were added to buses to simulate actual load conditions. The bus loading was based on a maximum of 80% of each building transformer full load rating evenly distributed.

2.7 Equipment Condition Evaluation

Inspect the electrical equipment over the course of data collection and assign an equipment condition to each item:

Grade A- “Excellent” Condition. Majority of useful life span remains.

Grade B- “Good” Condition. Over half of useful life span remains.

Grade C- “Average” Condition. Less than half of useful life span remains.

Grade D- “Poor” Condition. Past assigned useful life. Failure is not imminent.

Grade F- “Critical” Condition. Needs immediate attention.

2.8 Generator and ATS Evaluation

2.8.1 Provide a narrative describing the existing emergency power systems and provide description of each emergency generator, physical location, size (kW and amp capacity), Voltage, configuration (phase, wire, circuit number, age, overall condition.

2.8.2 For all automatic transfer switches, determine if the correct 3-pole or 4-pole switches are used.

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3.0 FINDINGS AND RECOMMENDATIONS

3.1 Short Circuit Analysis

Based on the model created, an analysis was performed representing the worst case configuration and the available fault duties were compared to the interrupting ratings of the devices studied.

There are twenty-seven (27) locations where the available fault current exceeds the self-protected rating for the equipment. Series combination rating cannot be applied here.

1) Building 115:

a) Control Panel 115 CH-1 CP. Rated 5kA, available 19.48kA. Needs to be field evaluated for a higher Short-circuit current rating (SCCR).

b) Panel 115-1-03A-2B: The breakers are rated for 10kA, available is 12.53kA. Note 1

c) Panel 115-1-03A-2D. The breakers are rated for 10kA, available is 12.12kA. Note 1

d) Panel 115-1-03A-2E. The breakers are rated for 10kA, available is 13.8kA. Note 1

2) Building 128:

a) Panel 128 Emergency: The breakers are rated for 10kA, available is 11.13kA. Note 1

b) Panel 128 Pnl 1-03: The breakers are rated for 10kA, available is 11.59kA. Note 1

c) SWBD 128-1: The breakers are rated for 10kA, available is 14.72kA. Note 1

d) Panel 128Mach Shop: The breakers are rated for 10kA, available is 12.67kA. Note 1

3) Building 143:

a) Panel 143-1-1-1A: The breakers are rated for 10kA, available is 15.42kA. Note 1

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4) Building 305:

a) Panel 305-1-06: The breakers are rated for 10kA, available is 11.13kA. Note 1

b) Panel 305-1-08A: The breakers are rated for 10kA, available is 10.53kA. Note 1

c) Panel 305CH-2: Rated 5kA, available 10.22kA. Needs to be field evaluated for a higher Short-circuit current rating

(SCCR)

5) Building 307:

a) Panel Pnl-1A: The breakers are rated for 10kA, available is 11.5kA. Note 1

b) Panel Pnl-1B: The breakers are rated for 10kA, available is 10.34kA. Note 1

c) Panel Pnl-1C: The breakers are rated for 10kA, available is 13.53kA. Note 1

d) Panel Pnl-1D: The breakers are rated for 10kA, available is 13.17kA. Note 1

e) Panel Pnl-GA: The breakers are rated for 10kA, available is 13.21kA. Note 1

f) Panel Pnl-GB: The breakers are rated for 10kA, available is 14.57kA. Note 1

g) Panel Pnl-GC: The breakers are rated for 10kA, available is 15.49kA. Note 1

6) Building 315:

a) Control Panel 315 CH-1 CP: Rated 5kA, available 18.46kA. Needs to be field evaluated for a higher Short-circuit current rating (SCCR)

7) Building 320:

a) SWBD 320E-1: The 100A breakers CB320ELEV1 and CB320ELEV2 are rated for 10kA, available is 16.52kA.

Note 1. Recommend replace these breakers with ones having a SCCR of at least 22 kA.

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8) Building 330:

a) Panel HNBD3 (US1C distribution). The breakers are rated for 18kA, available is 21.01kA. Note 1

9) Building 402:

a) SWBD 402 MDP-1: The breaker for CB-PNL402-1-5 is rated for 10kA, available is 24.51kA. Note 1. Recommend replace this breaker with one having a SCCR of at least 30 kA.

10) Building 408:

a) Panel 408-1-08: The breakers are rated for 10kA, available is 12.79kA. Note 1

11) Building 410:

a) Panel 410-1-04: The breakers are rated for 10kA, available is 24.81kA. Note 1

b) Panel 410-1-04-21: The breakers are rated for 10kA, available is 11.11kA. Note 1

c) Panel 410E-1-5: The breakers are rated for 14kA, available is 14.65kA. Note 1

NOTE 1: It is recommended that any under-rated panelboard be reviewed for panelboard/breaker replacement or other means such as providing series rating (if applicable).

All other equipment analyzed were found to have acceptable self or series protected ratings.

A table summarizing the ratings of the equipment analyzed versus the available fault duties is contained in Appendix 2. Complete computer output of the input data and fault case run is contained in Appendix 4.

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3.2 Coordination Study

3.2.1 Due to the restriction of the size difference between upstream OCPD (overcurrent protective devices) and downstream OCPDs, coordination between the upstream OCPDs and the downstream circuit breakers is not selective. Refer to TCCs at Appendix 5 for reference.

3.2.2 It may be noted that selective coordination is required for hospitals and other buildings housing critical care areas or utilizing life-support equipment and buildings that provide essential utilities or services for the operation of critical-care areas or electrical life-support equipment.

Overcurrent protective devices serving these essential electrical system shall selectively coordinate for the period of time that a fault’s duration extends beyond 0.1 second (NFPA 99 article 6.4.2.1.2).

3.2.3 It may be noted that selective co-ordination at all levels upto 0.1 secs was not required before the NEC 2005. However this may be looked into for any renovation projects.

1) Building 108:

a) TCC#1: Building 108-Panel DP-1: Downstream feeder breaker for VFDs is same size as main (150A). Selective Coordination not possible.

2) Building 118:

a) TCC#5 and #6: Building 118: TX-T-4-1 is a 50 kVA transformer (12470-240V, single phase). Secondary current is 208A. Secondary breaker has to be <1.25x (Max 300A). Present breaker is 600A. (Ref NEC Table 450.3(A)).

3) Building 126:

a) TCC#11: Building 126-126-1-10. Upstream and downstream breakers of same size (150A). Coordination not possible.

4) Building 128:

a) TCC#21: Building 128-ATS-128: Upstream (100A) and downstream feeder breakers (70A) cannot coordinate.

Selective Coordination not possible.

b) TCC#23: Building 128-Panel 01A-04: Upstream (100A) and downstream feeder breakers (60A) cannot coordinate.

Selective Coordination not possible.

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5) Building 135:

a) TCC#41: Building 135-Panel 135-1-1: Upstream (150A) and downstream breakers (150A) cannot coordinate.

Selective Coordination not possible.

b) TCC#42: Building 135-Panel 135-1. Upstream (400A) and downstream feeder breaker (150A) cannot coordinate.

Selective Coordination not possible

c) TCC#45: Building 135-Panel 135-03A-02: Upstream (150A) and downstream breaker (60A) cannot coordinate.

Selective Coordination not possible.

6) Building 147:

a) TCC#52 and 57: Building 147-147E-1: Upstream (600A and 400A) and downstream breaker (350A) cannot coordinate. Selective Coordination not possible.

b) TCC#59: Building 147-Panel 147E-1-05-01B-01:

Upstream (225A) breaker and fuse, and downstream breaker (60A) cannot coordinate. Selective Coordination not possible.

c) TCC#61: Building 147-Panel 147E-1-06-3C: Upstream (125A) breaker and downstream feeder breakers (100A) cannot coordinate. Selective Coordination not possible.

7) Building 305:

a) TCC#66: Building 305-Panel 305-1-02A: Upstream (400A) breakers and downstream feeder breaker (225A) cannot coordinate. Selective Coordination not possible.

b) TCC#69: Building 305-Panel 305-1-04A: Upstream (400A) breakers and downstream feeder breaker (200A) cannot coordinate. Selective Coordination not possible.

c) TCC#71: Building 305-Panel 305-1-05: Upstream (400A) breakers and downstream feeder breaker (225A) cannot coordinate. Selective Coordination not possible.

d) TCC#76: Building 305-Panel 305-1-09A: Upstream (225A)…