assumption university thailand ee4503 electrical systems design cable 1

Assumption University Thailand

EE4503Electrical Systems Design

Cable

1


Topics

• Introduction to Cables

• Cables for low voltage

• Cables for high voltage

• Cable selection

2


Cables

• Functionality

– Conduct electrical power from one point to other

• Components

– Conductor

– Insulator (optional)

3


Cables - Conductor

• Physical

– Solid

– Strand: flexible, reduce skin effect

• Material

– Copper

– Aluminum

4


Cables - Conductor

http://www.cedengineering.com/upload/Electrical%20Conductors.pdf http://www.geindustrial.com/Newsletter/Aluminum_vs_Copper.pdf

5


Cables - Insulator

• Prevent the physical contact: between two

cables, cable-to-ground

– Physical durable e.g. impact, heat

– Chemical durable, e.g. erosion

• Commonly used

– Polyvinyl Chloride (PVC)

– Cross linked Polyethylene (XLPE)6


Cables - Insulator

http://www.gridcables.com/power-cable.html

7


Cables for High Voltage

• Withstand the high voltage: insulator (if any)

need to be good.

• Long distance transmission: Cable cost &

Installation cost (e.g. electricity pole)

• Two main types

– Bare Wires (reduce cost)

– Insulated Wires8


High Voltage CablesBare Wires

• Made of Aluminum for lower cost

• Transmission system (not distribution system

for safety): Reduce usage: animals, accident, etc.

• AAC: All Aluminum Cable

• AAAC: All Aluminum Alloy Cable

• ACSR: Aluminum Conductor Steel Reinforced9


High Voltage CablesBare Wires

• AAC: Basic type, for shorter span

• AAAC: Improve the property of Aluminum by making it as an alloy stronger, larger span, corrosion resistance (e.g. sea)

• ACSR: Insert the steel in the core to have more tension.

10


High Voltage CablesInsulated Wires

• For safety and prevent interruption

• PIC: Partial Insulated Cable

• SAC: Space Aerial Cable

• XLPE: Cross-linked

Polyethylenehttp://www.huffingtonpost.co.uk/2012/03/26/northamptonshire-fire-crew-hot-air-balloonist_n_1378971.html

11


High Voltage CablesInsulated Wires - PIC

http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/33kv_oc.pdf

12


High Voltage CablesInsulated Wires - SAC

http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/35kv_cc.pdf

13


High Voltage CablesInsulated Wires - XLPE

http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/115kv_ce.pdf

14


Cables for Low Voltage

• Below 750V

• Conductor: Aluminum or Copper

• Insulator: PVC or XLPE

• Number of Conductor: 1 or many

• Special Type to suite the need: Fire Retardent

15


Cables for Low Voltage(see pdf)

• PVC

– NAY (aluminum)

– THW

– VAF

– VCT

– NYY (double shealth)

• XLPE

– CV

• MI

• Fire Safety Cable

– Flame Retardant

– Fire Resistant16


Cables for Low VoltageFire Resistant Cable

• Flame Retardancy

• Flame Propagation

• Acid and Corrosive Gas Emission

• Smoke Emission

• Fire Resistance (Circuit Integrity)

17


Cables for Low VoltageFire Resistant Cable

• Fire Alarm System

• Building Automation System

• Emergency Lighting System

• Public Address System

• Standby Power System

• Computer Network System

• Closed Circuit TV System

• Elevators and Escalators System

• Fire Pumps and Pressurized Stairs

• Etc.

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Assignments

• Take pictures of the cable that you can see and classify the types of those cables.

• Take pictures of the name-plates

19


Cable Selection

• Usage: Table 5-16 (EIT Standard 2001-51) for low

voltage cable

• Rated Voltage: 300V or 750V

• Rated Current

• Multiple Conductors

• Voltage Drop20


Cable Selection – Rated Current

• Size of Conductor

• Type of Insulator

• Ambient Temperature

• Installation Conditions:

– Calculation: BCC - Technical_data_Cable

– Table: BCC - InstallationGuide, AS_NZS_3008.1.1_2009

21


Cable Selection – Rated CurrentInstallation Conditions (3.1)

Handout: BCC - Installation Guide.pdf

22


Cable Selection – Rated CurrentInstallation Conditions (3.1t)


23




24




25




26




27


Cable Selection – Rated CurrentNumber of Cables in a Conduit


28


Cable Selection – Multiple Conductors

• To increase the rated current


29


Cable Selection – Multiple Conductors

• Only for cable from 50 sq.mm. and up

• Same type of cables

• Same length

• Same wiring method

30


Cable Selection – Voltage Drop

• Voltage drop due to the impedance of the cable

• NEC

– Main incoming to load: no more than 5%

– Feeder: no more than 2%

– Branch Circuit: no more than 3%

31



32

Zcable

Zload

220 V (AC)



• Load: is from the consumption and power factor: or

• Cable: is from the table ( and )

– depends on the wiring configurations.

33


Cable Selection – Voltage DropCalculation

34

• Use the normal voltage divider in the calculation.

– =

– =

– ????


Cable Selection – Voltage DropCalculation

http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pour-visualisation_basse_def.pdf

35


Cable Selection – Rated CurrentCalculation

36



Equivalent CircuitsImpedance: table for PVC cables

and

37

Size () Resistance()

Reactance()

2.5 7.400 0.155

4 4.625 0.141

6 3.083 0.131

10 1.850 0.121

16 1.156 0.113

25 0.740 0.107

35 0.529 0.103

50 0.370 0.100

Electrical Systems Design: ประสิ�ทธิ์�� พิ�ทยพิ�ฒน์�

Size () Resistance()

Reactance()

70 0.264 0.097

95 0.195 0.096

120 0.154 0.094

150 0.123 0.092

185 0.100 0.091

240 0.077 0.090

300 0.062 0.089

400 0.051 0.088


Cable Selection – Rated CurrentFrom Table

38



Cable Selection – General Rules

• 20% to 25% factor.

• Using current or VA (not power).

39


Cable Selection – Examples

• Water Heater 6kW

– in Air or in Metal Conduit

• Microwave 2,300VA

• Industrial Heater 40kW, 400V 3phase

– 40oC or 50oC

40


Cable Selection – Examples

• Motor 37kW, 400V, In=72A

– DOL & Star-Delta

• Motor 60kW, 400V, pf.=0.8

• Room

– receptacles 2.5kVA

– lighting 500VA41


Handout

• BCC - Installation Guide

• HELUKABEL - Installation Operating Conditions

• AS_NZS_3008.1.1_2009

42


• Electrical Systems Design: ประสิ�ทธิ์�� พิ�ทยพิ�ฒน์�• Thai Electrical Code 2002: EIT Standard 2001-51

• http://www.bangkokcable.com

• http://www.thaiyazaki-electricwire.co.th

• Electrical Installation Guide 2010: schneider-electric

Reference

43

http://www.bangkokcable.com/

http://www.thaiyazaki-electricwire.co.th/

assumption university thailand ee4503 electrical systems design cable 1

Documents

cables cables

low voltage cables

high voltage cable selection

cable table

cable cost installation

aluminum cable aaac

current number of cables

aluminum alloy cable