260573 - OCP Device Coordination Study.pdf

Jesse Brown VAMC May 30, 2020 VA: 537-15-160 Emergency Renovations 100% Construct ion Documents Chicago, IL 60064 01-01-18

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SECTION 26 05 73

OVERCURRENT PROTECTIVE DEVICE COORDINATION STUDY

PART 1 - GENERAL

1.1 DESCRIPTION

A. This section specifies the overcurrent protectiv e device coordination study, related calculations and analysis, indicated as the study in this section.

B. A short-circuit and selective coordination study , and arc flash calculations and analysis shall be prepared for the electrical overcurrent devices to be installed under this proj ect.

C. The study shall present a well-coordinated time- current analysis of each overcurrent protective device from the new pan els up to the utility source and the on-site generator sources.

1.2 RELATED WORK

A. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL IN STALLATIONS: General electrical requirements that are common to more tha n one section of

Division 26.

B. Section 26 23 00, LOW-VOLTAGE SWITCHGEAR: Low-vo ltage switchgear.

C. Section 26 24 13, DISTRIBUTION SWITCHBOARDS: Low -voltage distribution switchboards.

D. Section 26 24 16, PANELBOARDS: Low-voltage panel boards.

1.3 QUALITY ASSURANCE

A. Quality Assurance shall be in accordance with Pa ragraph, QUALIFICATIONS

(PRODUCTS AND SERVICES) in Section 26 05 11, REQUIR EMENTS FOR

ELECTRICAL INSTALLATIONS.

B. The study shall be prepared by the equipment man ufacturer, and performed by the equipment manufacturer’s licensed electrical engineer.

1.4 SUBMITTALS

A. Submit in accordance with Paragraph, SUBMITTALS in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS, and the following requirements:

1. Product data on the software program to be used for the study.

Software shall be in mainstream use in the industry , shall provide device settings and ratings, and shall show selecti ve coordination by time-current drawings.

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2. Complete study as described in paragraph 1.6. Su bmittal of the study shall be well-coordinated with submittals of the sh op drawings for equipment in related specification sections.

3. Certifications: Two weeks prior to final inspect ion, submit the following.

a. Certification by the Contractor that the overcur rent protective devices have been set in accordance with the approv ed study.

1.5 APPLICABLE PUBLICATIONS

A. Publications listed below (including amendments, addenda, revisions, supplements, and errata) form a part of this specif ication to the extent referenced. Publications are referenced in t he text by designation only.

B. Institute of Electrical and Electronics Engineer s (IEEE):

241-90..................Recommended Practice Electr ical Systems in

Commercial Buildings

242-03..................Recommended Practice for Pr otection and

Coordination of Industrial and Commercial Power

Systems

399-97..................Recommended Practice for In dustrial and

Commercial Power Systems Analysis

1584-02.................Performing Arc-Flash Hazard s Calculations

1584A-04................Performing Arc-Flash Hazard s Calculations –

Amendment 1

1584B-11................Performing Arc-Flash Hazard s Calculations –

Amendment 2

C. National Fire Protection Association (NFPA):

70-17...................National Electrical Code (N EC)

70E-18..................Standard for Electrical Saf ety in the Workplace

99-18...................Health Care Facilities Code

1.6 STUDY REQUIREMENTS

A. The study shall be in accordance with IEEE and N FPA standards.

B. The study shall include one line diagram, short- circuit and ground fault analysis, protective coordination plots for a ll overcurrent protective devices, and arc flash calculations and analysis.

C. One Line Diagram:

1. Show all electrical equipment and wiring to be p rotected by the overcurrent devices.

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2. Show the following specific information:

a. Calculated fault impedance, X/R ratios, and shor t-circuit values at each feeder and branch circuit bus.

b. Relay, circuit breaker, and fuse ratings.

c. Generator kW/kVA and transformer kVA and voltage ratings, percent impedance, X/R ratios, and wiring connections.

d. Voltage at each bus.

e. Identification of each bus, matching the identif ication on the drawings.

f. Conduit, conductor, and busway material, size, l ength, and X/R ratios.

D. Short-Circuit Study:

1. The study shall be performed using computer soft ware designed for this purpose. Pertinent data and the rationale emp loyed in developing the calculations shall be described in t he introductory remarks of the study.

2. Calculate the fault impedance to determine the a vailable short-circuit and ground fault currents at each bus. Inco rporate applicable motor and/or generator contribution in d etermining the momentary and interrupting ratings of the overcurre nt protective devices.

3. Present the results of the short-circuit study i n a table. Include the following:

a. Device identification.

b. Operating voltage.

c. Overcurrent protective device type and rating.

d. Calculated short-circuit current.

E. Coordination Study:

1. Prepare the coordination curves to determine the required settings of overcurrent protective devices to demonstrate se lective coordination. Graphically illustrate on log-log pap er that adequate time separation exists between devices, including t he utility company upstream device if applicable. Plot the spe cific time-current characteristics of each overcurrent pr otective device in such a manner that all devices are clearly depic ted.

2. The following specific information shall also be shown on the coordination curves:

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a. Device identification.

b. Potential transformer and current transformer ra tios.

c. Three-phase and single-phase ANSI damage points or curves for each cable, transformer, or generator.

d. Applicable circuit breaker or protective relay c haracteristic curves.

e. No-damage, melting, and clearing curves for fuse s.

f. Transformer in-rush points.

3. Develop a table to summarize the settings select ed for the overcurrent protective devices. Include the followi ng in the table:

a. Device identification.

b. Protective relay or circuit breaker potential an d current transformer ratios, sensor rating, and available an d suggested pickup and delay settings for each available trip c haracteristic.

c. Fuse rating and type.

F. Arc Flash Calculations and Analysis:

1. Arc flash warning labels shall comply with Secti on 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS.

2. Arc flash calculations shall be based on actual over-current protective device clearing time. Maximum clearing time shall be in accordance with IEEE 1584.

3. Arc flash analysis shall be based on the lowest clearing time setting of the over-current protective device to mi nimize the incident energy level without compromising selectiv e coordination.

4. Arc flash boundary and available arc flash incid ent energy at the corresponding working distance shall be calculated for all electrical power distribution equipment specified i n the project, and as shown on the drawings.

5. Required arc-rated clothing and other PPE shall be selected and specified in accordance with NFPA 70E.

1.7 ANALYSIS

A. Analyze the short-circuit calculations, and high light any equipment determined to be underrated as specified. Propose s olutions to effectively protect the underrated equipment.

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1.8 ADJUSTMENTS, SETTINGS, AND MODIFICATIONS

A. Final field settings and minor modifications of the overcurrent protective devices shall be made to conform with th e study, without additional cost to the Government.

PART 2 - PRODUCTS (NOT USED)

PART 3 - EXECUTION (NOT USED)

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