electrical engineering basics - what design engineers need to know

Initial Design DiscussionInitial Design DiscussionWhat the Project Engineer Needs What the Project Engineer Needs

to Knowto Know

NJWEA Technology Transfer NJWEA Technology Transfer Seminar Seminar 26-Sep-0726-Sep-07

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AgendaAgenda

What the Project Engineer Needs to KnowWhat the Project Engineer Needs to Know Electrical Design ElementsElectrical Design Elements

The LoadThe Load The SourceThe Source ProtectionProtection Monitor and Control Monitor and Control

SummarySummary Q & AQ & A


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What the Project Engineer Needs What the Project Engineer Needs to Knowto Know

Information from the PM – The Load ListInformation from the PM – The Load List What are the loads?What are the loads?

MotorsMotors HeatersHeaters

What are the hp or kw ratings?What are the hp or kw ratings? Where are they located?Where are they located?

OutdoorsOutdoors IndoorsIndoors

What is the classification of the What is the classification of the area?area?

Is a control panel specified?Is a control panel specified?


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The LoadThe Load

Utilizes power Utilizes power (voltage and current)(voltage and current)

Has electrical ratingsHas electrical ratings Must be protectedMust be protected Must be controlledMust be controlled Can be monitoredCan be monitored

© Baldor Electric Co.

© LDPI, Inc.


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Electrical Design ElementsElectrical Design Elements

Magnitude, quality, characteristics, demand, Magnitude, quality, characteristics, demand, coincidence or diversity of loads, and load coincidence or diversity of loads, and load factorsfactors

Service, distribution, and utilization voltages Service, distribution, and utilization voltages and voltage regulationand voltage regulation

Flexibility, reliability, continuity, and safetyFlexibility, reliability, continuity, and safety Operation and maintenanceOperation and maintenance Special requirements associated with the Special requirements associated with the

process and process environment process and process environment Legally required, optional Legally required, optional

standby/emergency systemsstandby/emergency systems Energy conservation and DOE complianceEnergy conservation and DOE compliance


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Electrical Design ElementsElectrical Design Elements

Service, distribution, and utilization Service, distribution, and utilization voltages and voltage regulationvoltages and voltage regulation Electrical Site planElectrical Site plan Utility connectionsUtility connections


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Electrical Design DevelopmentElectrical Design Development For new facilities power designFor new facilities power design

Determine total plant load (building and process)Determine total plant load (building and process) Develop single line diagramDevelop single line diagram Model loads Model loads Evaluate protective device settings and coordinateEvaluate protective device settings and coordinate Document final protective settingsDocument final protective settings

For existing facilities power designFor existing facilities power design Document existing conditions – confirm and revise existing single Document existing conditions – confirm and revise existing single

line diagramline diagram Evaluate the system and prepare a reportEvaluate the system and prepare a report Update single line diagramUpdate single line diagram Implement recommendationsImplement recommendations Model new loads on the existing system and re-evaluateModel new loads on the existing system and re-evaluate Document protective settingsDocument protective settings


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The Power Source The Power Source

Flywheel UPS© Liebert

Engine Generator Set© Cummins Power Generation

Pole Mounted Transformers Pad Mounted Transformers


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Current installations Current installations includeinclude Government Government

telecommunications telecommunications and data storage and data storage centerscenters

Medical facilitiesMedical facilities National television National television

networksnetworks

Flywheel UPS


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AdvantagesAdvantages Smaller foot printSmaller foot print Green technologyGreen technology

Non toxicNon toxic Non corrosiveNon corrosive

Quiet operationQuiet operation Lower long term costsLower long term costs

Flywheel UPS


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The Power SourceThe Power Source

DisadvantagesDisadvantages Higher initial costHigher initial cost Short term loadingShort term loading

Example: The Pentadyne VSSdc unit at WBRZ is rated at Example: The Pentadyne VSSdc unit at WBRZ is rated at 160 kilowatt for 13 seconds.160 kilowatt for 13 seconds.

http://www.energyandpowermanagement.com/CDA/Articles


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Substation 13.2kV; 69kV; 115kV

Plant Distribution4160V; 480V; 208V

Control120V

Signal24V

Nominal System VoltagesNominal System Voltages


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Working ClearancesWorking Clearancesunder 600Vunder 600V

NEC® 2005

Clearances shall be provided& maintained to permit ready and safe operation and maintenance

Examination Adjustment Servicing Maintenance


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2005 NEC Article 110.26 Spaces About Electrical Equipment (C) Entrance to Working Space. (2) Large Equipment. For equipment rated 1,200A or more, an entrance measuring not less than 24 in. wide and 61/2 ft high, is required at each end of the working space. Where the entrance to the working spacehas a door, the door must open out and be equipped with panic hardware or other devices that open under simple pressure.

This material was extracted from Mike Holt Training Materials copyright 2007 by permission.Visit www.NECCode.com or call 1.888.NEC.Code (632-2633) for more information.

NEC® 2002


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Working ClearancesWorking Clearancesover 600Vover 600V

NEC® 2005


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ProtectionProtection Fixed Trip (Inverse Time)Fixed Trip (Inverse Time)

15A – 50A [ 5A]15A – 50A [ 5A] 60A – 110A [10A]60A – 110A [10A] 125A -300A [25A]125A -300A [25A] 300A – 500A [50A]300A – 500A [50A] 600 – 800 [100A]600 – 800 [100A] 1000 1000 12001200 16001600 20002000 25002500 30003000 40004000 50005000 60006000

Low Voltage Circuit Breakers© Square D


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ProtectionProtection

Low Voltage Fuses [250V – 600V]Low Voltage Fuses [250V – 600V] Dual-element, time-delay fuse Class JDual-element, time-delay fuse Class J Current-limiting Class RK1Current-limiting Class RK1 Time-delay, current-limiting, rejection-Time-delay, current-limiting, rejection-

type Class CCtype Class CC Time-delay Class LTime-delay Class L Dual-element, time-delay fuse Class Dual-element, time-delay fuse Class

RK5RK5 Medium voltageMedium voltage


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ProtectionProtection Circuit breakers tested to show Circuit breakers tested to show

arc flash hazard risk category as arc flash hazard risk category as referenced by NFPA70E referenced by NFPA70E

800 A to 6000 A frames, fixed and 800 A to 6000 A frames, fixed and draw-out draw-out

Rated for AC voltage systems Rated for AC voltage systems through 600 V (635 V ANSI) through 600 V (635 V ANSI)

Visual contact wear indicators Visual contact wear indicators Field-installable accessories Field-installable accessories

common to all standards common to all standards Four interchangeable Micrologic Four interchangeable Micrologic

trip units to choose from trip units to choose from Available PowerLogic® based Available PowerLogic® based

power metering and monitoring power metering and monitoring capabilities capabilities

Available protective relay functions Available protective relay functions as defined by ANSI C37.2 and as defined by ANSI C37.2 and C37.90 C37.90

Power Circuit Breakers with Arc Flash Protection

© Square D


2020


Vacuum circuit breakersVacuum circuit breakers Rated at 5kV, 15kV, Rated at 5kV, 15kV,

27kV and 38kV27kV and 38kV ANSI C37.09 StandardANSI C37.09 Standard

Protective relaysProtective relays Over voltageOver voltage Under voltageUnder voltage Phase reversalPhase reversal Single phaseSingle phase

Medium Voltage Circuit Breaker© Eaton Cutler-Hammer


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Medium Voltage FusesMedium Voltage Fuses E rated (transformers and feeders)E rated (transformers and feeders) Fast-actingFast-acting R rated (motor circuit protection)R rated (motor circuit protection) H & N (high surge)H & N (high surge) K (fast)K (fast) T (slow)T (slow)


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Monitor and ControlMonitor and Control

MetersMeters Utility and submeters [kW-h]Utility and submeters [kW-h] Voltage - voltmetersVoltage - voltmeters Current - ammetersCurrent - ammeters Flow – flow metersFlow – flow meters


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For Motor LoadsFor Motor Loads Variable Frequency ControllersVariable Frequency Controllers Reduced Voltage StartersReduced Voltage Starters Delta-Wye StartersDelta-Wye Starters


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For Process DevicesFor Process Devices Control ValvesControl Valves Pressure SwitchesPressure Switches Level SwitchesLevel Switches


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SummarySummary Electrical Design categories can be defined as Electrical Design categories can be defined as

Load, Load, Source,Source, Protection Protection Control and monitoringControl and monitoring

Load lists provided by the PM are used to develop single line Load lists provided by the PM are used to develop single line diagrams and P&ID’sdiagrams and P&ID’s

The power source to the load is determined based on the site The power source to the load is determined based on the site factors and load requirementsfactors and load requirements


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SummarySummary Electrical systems require protectionElectrical systems require protection

Electrical protectionElectrical protection Over currentOver current Over voltageOver voltage Phase reversalPhase reversal Transients Transients

Physical protection from the environmentPhysical protection from the environment NEMA rated enclosuresNEMA rated enclosures


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SummarySummary Load lists are used to develop integrated, system documentsLoad lists are used to develop integrated, system documents Single line diagrams – power Single line diagrams – power

Used for road maps for the facilityUsed for road maps for the facility Safe shut downsSafe shut downs Clear operationsClear operations

Used for short circuit and coordination studiesUsed for short circuit and coordination studies Guide for impact studiesGuide for impact studies

Process &Instrumentation DiagramsProcess &Instrumentation Diagrams Control Control MonitoringMonitoring


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DiscussionDiscussion

Thank You!


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AcknowledgementsAcknowledgements

electrical engineering basics - what design engineers need to know

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