Naval Facilities Engineering Command 200 Stovall Street

Alexandria, Virginia 22332-2300

Electric Power Distribution Systems

Operations

NAVFAC MO-201 April 1990

SN 0525-LP-320-1900

FOREWORD

This manual on electric power distribution systems is one of a series developed to aid utilitysupervisory personnel at shore establishments in the performance of their duties. It includesinformation obtained from extensive research of current literature on the subject and preferredpractices based on practical experience. The principles and procedures described are inaccordance with national professional society, association, and institute codes.

Additional information concerning procedures, suggestions, recommendations ormodifications that will improve this manual are invited and should be submitted throughappropriate channels to the Commander, Naval Facilities Engineering Command, (Attention: Code 165), 200 Stovall Street, Alexandria, VA 22332-2300.

This publication has been reviewed and approved in accordance with the Secretary of theNavy Instruction 5600.16A and is certified as an official publication of the Naval FacilitiesEngineering Command. It cancels and supersedes Operation of Electric Power DistributionSystems, NAVFAC MO-201, November 1963, in its entirety.

D. B. CAMPBELL Assistant Commander for Public Works Centers and Departments

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ABSTRACT

Application principles and procedures for the operation of electric power distribution systemsand associated major apparatus are presented. The contents include principles of power systems,cabling systems, electrical equipment, power system protection and coordination, instrumentsand meters, operational procedures, and electrical utilization systems.

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CHANGE CONTROL SHEET

Document all changes, page replacements, and pen and ink alterations posted in this manual.

AMENDMENT AMENDMENTNUMBER DATE

POST DATE POSTED BY(LAST NAME)

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CONTENTS PAGE

CHAPTER 1 PRINCIPLES OF POWER SYSTEMS 1-1 1.1 Typical Power Network............................................................................ 1-1 1.2 Electric Power Generation........................................................................ 1-2 1.3 Alternating Current Power Transmission System.................................... 1-3 1.4 Primary Distribution Systems................................................................... 1-4 1.5 Secondary Distribution Systems............................................................... 1-9 1.6 Emergency and Standby Power Systems.................................................. 1-15

CHAPTER 2 POWER DISTRIBUTION CABLE SYSTEMS 2-1 2.1 Cable Specifications................................................................................. 2-1 2.2 Cable Construction................................................................................... 2-1 2.3 Cable Ratings and Selection Criteria........................................................ 2-5 2.4 Types of Cable Installations..................................................................... 2-7 2.5 Power System Applications...................................................................... 2-10

CHAPTER 3 POWER SYSTEM ELECTRICAL EQUIPMENT 3-1 3.1 Major Apparatus....................................................................................... 3-1 3.2 Transformers............................................................................................. 3-2 3.3 Voltage Regulators.................................................................................... 3-16 3.4 Switches.................................................................................................... 3-21 3.5 Circuit Breakers........................................................................................ 3-26 3.6 Automatic Circuit Reclosers..................................................................... 3-38 3.7 Power Capacitors...................................................................................... 3-44 3.8 Distribution Substation............................................................................. 3-53

CHAPTER 4 POWER SYSTEM PROTECTION AND COORDINATION 4-1 4.1 System Protection Methods...................................................................... 4-1 4.2 Short-Circuit Currents.............................................................................. 4-2 4.3 Relays....................................................................................................... 4-8 4.4 Applied Protective Relaying.................................................................... 4-15 4.5 Fuses........................................................................................................ 4-19 4.6 Low-Voltage Circuit Breakers................................................................. 4-25 4.7 System Coordination Study..................................................................... 4-28

CHAPTER 5 POWER SYSTEM INSTRUMENTS AND METERS 5-1 5.1 Instrumentation and Metering.................................................................. 5-1 5.2 Instruments............................................................................................... 5-3 5.3 Meters....................................................................................................... 5-6

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CHAPTER 6 POWER SYSTEM OPERATION 6-1 6.1 Power System Structure........................................................................... 6-1 6.2 Control Center Procedures....................................................................... 6-2 6.3 Switchboards............................................................................................ 6-5 6.4 Safety and Environmental Requirements................................................. 6-8

CHAPTER 7 ELECTRICAL UTILIZATION SYSTEMS 7-1 7.1 System Voltages....................................................................................... 7-1 7.2 Equipment Nameplate Ratings and Nominal System Voltages................ 7-1 7.3 Street Lighting Systems............................................................................ 7-3

CHAPTER 8 MANAGING THE OPERATION OF ELECTRICAL DISTRIBUTION SYSTEMS 8-1

8.1 Operations Overview................................................................................. 8-1 8.2 Operations Management............................................................................ 8-1 8.3 Maintenance Management......................................................................... 8-9 8.4 System Planning Studies............................................................................ 8-14

CHAPTER 9 NEW AND EMERGING TECHNOLOGY 9-1 9.1 Supervisory Control and Data Acquisition................................................ 9-1 9.2 Control Circuits and Devices..................................................................... 9-4 9.3 Cogeneration.............................................................................................. 9-6 9.4 Variable Speed Electric Drive Systems..................................................... 9-7

APPENDIX A Operating Responsibilities and Organizational Relationships...... A-1

BIBLIOGRAPHY.................................................................................... Bibliography-1

INDEX................................................................................................................. Index-1

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FIGURES

FIGURE NO. TITLE PAGE

1-1 Typical Electric Power Generation, Transmission, and Distribution System.............. 1-11-2 Typical Distribution Substation Arrangements............................................................ 1-51-3 Typical Bus Arrangements........................................................................................... 1-71-4 Four Primary Feeder Arrangements............................................................................. 1-81-5 Conventional Simple-Radial Distribution System....................................................... 1-111-6 Expanded Radial Distribution System......................................................................... 1-111-7