Cable

Report
Assumption University
Thailand
EE4503
Electrical Systems Design
Cable
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Assumption University
Thailand
Topics
• Introduction to Cables
• Cables for low voltage
• Cables for high voltage
• Cable selection
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Cables
• Functionality
– Conduct electrical power from one point to
other
• Components
– Conductor
– Insulator (optional)
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Cables - Conductor
• Physical
– Solid
– Strand: flexible, reduce skin effect
• Material
– Copper
– Aluminum
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Cables - Conductor
http://www.cedengineering.com/upload/Electrical%20Conductors.pdf
http://www.geindustrial.com/Newsletter/Aluminum_vs_Copper.pdf
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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)
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Cables - Insulator
http://www.gridcables.com/power-cable.html
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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 Wires
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High Voltage Cables
Bare 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 Reinforced
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Thailand
High Voltage Cables
Bare 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.
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High Voltage Cables
Insulated Wires
• For safety and prevent
interruption
• PIC: Partial Insulated Cable
• SAC: Space Aerial Cable
• XLPE: Cross-linked
Polyethylene
http://www.huffingtonpost.co.uk/2012/03/26/northamptons
hire-fire-crew-hot-air-balloonist_n_1378971.html
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High Voltage Cables
Insulated Wires - PIC
http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/33kv_oc.pdf
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High Voltage Cables
Insulated Wires - SAC
http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/35kv_cc.pdf
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High Voltage Cables
Insulated Wires - XLPE
http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/115kv_ce.pdf
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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
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Cables for Low Voltage
• PVC
(see pdf)
• XLPE
– NAY (aluminum)
– CV
– THW
• MI
– VAF
• Fire Safety Cable
– VCT
– Flame Retardant
– NYY (double shealth)
– Fire Resistant
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Cables for Low Voltage
Fire Resistant Cable
• Flame Retardancy
• Flame Propagation
• Acid and Corrosive Gas Emission
• Smoke Emission
• Fire Resistance (Circuit Integrity)
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Cables for Low Voltage
Fire Resistant Cable
• Fire Alarm System
• Computer Network System
• Building Automation
System
• Closed Circuit TV System
• Public Address System
• Fire Pumps and Pressurized
Stairs
• Elevators and Escalators
• Emergency Lighting System
System
• Standby Power System
• 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
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Cable Selection
• Usage: Table 5-16 (EIT Standard 2001-51) for low
voltage cable
• Rated Voltage: 300V or 750V
• Rated Current
• Multiple Conductors
• Voltage Drop
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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
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Cable Selection – Rated Current
Installation Conditions (3.1)
Handout: BCC - Installation Guide.pdf
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Cable Selection – Rated Current
Installation Conditions (3.1t)
Handout: BCC - Installation Guide.pdf
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Assumption University
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Cable Selection – Rated Current
Installation Conditions (3.2)
Handout: BCC - Installation Guide.pdf
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Assumption University
Thailand
Cable Selection – Rated Current
Installation Conditions (3.2t)
Handout: BCC - Installation Guide.pdf
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Assumption University
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Cable Selection – Rated Current
Installation Conditions (3.3)
Handout: BCC - Installation Guide.pdf
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Cable Selection – Rated Current
Installation Conditions (3.3t)
Handout: BCC - Installation Guide.pdf
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Cable Selection – Rated Current
Number of Cables in a Conduit
Handout: BCC - Installation Guide.pdf
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Cable Selection – Multiple Conductors
• To increase the rated current
Handout: BCC - Installation Guide.pdf
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Cable Selection – Multiple Conductors
• Only for cable from 50 sq.mm. and up
• Same type of cables
• Same length
• Same wiring method
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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%
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Cable Selection – Voltage Drop
Zcable
220 V (AC)
Zload
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Cable Selection – Voltage Drop
• Load:  is from the consumption and
power factor:  =


or cos
−1
 =


• Cable:  is from the table ( and  )
–  depends on the wiring configurations.
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Cable Selection – Voltage Drop
Calculation
• Use the normal voltage divider in the
calculation.
–  = +
–  = ∗ ( +  ) +
– ????
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Cable Selection – Voltage Drop
Calculation
http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pourvisualisation_basse_def.pdf
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Cable Selection – Rated Current
Calculation
http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pourvisualisation_basse_def.pdf
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Equivalent Circuits
Impedance: table for PVC cables
 =  ∗  and  =  ∗ 
Size
( )
Resistance

( )
Reactance

( )
Size
( )
Resistance

( )
Reactance

( )
2.5
7.400
0.155
70
0.264
0.097
4
4.625
0.141
95
0.195
0.096
6
3.083
0.131
120
0.154
0.094
10
1.850
0.121
150
0.123
0.092
16
1.156
0.113
185
0.100
0.091
25
0.740
0.107
240
0.077
0.090
35
0.529
0.103
300
0.062
0.089
50
0.370
0.100
400
0.051
0.088




Electrical Systems Design: ประสิ ทธิ ์ พิทยพัฒน์
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Cable Selection – Rated Current
From Table
http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pourvisualisation_basse_def.pdf
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Cable Selection – General Rules
• 20% to 25% factor.
• Using current or VA (not power).
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Cable Selection – Examples
• Water Heater 6kW
– in Air or in Metal Conduit
• Microwave 2,300VA
• Industrial Heater 40kW, 400V 3phase
– 40oC or 50oC
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Cable Selection – Examples
• Motor 37kW, 400V, In=72A
– DOL & Star-Delta
• Motor 60kW, 400V, pf.=0.8
• Room
– receptacles 2.5kVA
– lighting 500VA
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Handout
• BCC - Installation Guide
• HELUKABEL - Installation Operating
Conditions
• AS_NZS_3008.1.1_2009
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Reference
• Electrical Systems Design: ประสิ ทธิ ์ พิทยพัฒน์
• Thai Electrical Code 2002: EIT Standard 2001-51
• http://www.bangkokcable.com
• http://www.thaiyazaki-electricwire.co.th
• Electrical Installation Guide 2010: schneider-electric
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