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EE4503 Electrical Systems Design. Cable. Topics. Introduction to Cables Cables for low voltage Cables for high voltage Cable selection. Cables. Functionality Conduct electrical power from one point to other Components Conductor Insulator (optional). Cables - Conductor. Physical
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Topics • Introduction to Cables • Cables for low voltage • Cables for high voltage • Cable selection
Cables • Functionality • Conduct electrical power from one point to other • Components • Conductor • Insulator (optional)
Cables - Conductor • Physical • Solid • Strand: flexible, reduce skin effect • Material • Copper • Aluminum
Cables - Conductor http://www.cedengineering.com/upload/Electrical%20Conductors.pdf http://www.geindustrial.com/Newsletter/Aluminum_vs_Copper.pdf
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)
Cables - Insulator http://www.gridcables.com/power-cable.html
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
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 Reinforced
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.
High Voltage CablesInsulated 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/northamptonshire-fire-crew-hot-air-balloonist_n_1378971.html
High Voltage CablesInsulated Wires - PIC http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/33kv_oc.pdf
High Voltage CablesInsulated Wires - SAC http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/35kv_cc.pdf
High Voltage CablesInsulated Wires - XLPE http://www.thaiyazaki-electricwire.co.th/products/pdf/edit_pdf/hvmvpc/115kv_ce.pdf
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
Cables for Low Voltage(see pdf) • PVC • NAY (aluminum) • THW • VAF • VCT • NYY (double shealth) • XLPE • CV • MI • Fire Safety Cable • Flame Retardant • Fire Resistant
Cables for Low VoltageFire Resistant Cable • Flame Retardancy • Flame Propagation • Acid and Corrosive Gas Emission • Smoke Emission • Fire Resistance (Circuit Integrity)
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.
Assignments • Take pictures of the cable that you can see and classify the types of those cables. • Take pictures of the name-plates
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
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
Cable Selection – Rated CurrentInstallation Conditions (3.1) Handout: BCC - Installation Guide.pdf
Cable Selection – Rated CurrentInstallation Conditions (3.1t) Handout: BCC - Installation Guide.pdf
Cable Selection – Rated CurrentInstallation Conditions (3.2) Handout: BCC - Installation Guide.pdf
Cable Selection – Rated CurrentInstallation Conditions (3.2t) Handout: BCC - Installation Guide.pdf
Cable Selection – Rated CurrentInstallation Conditions (3.3) Handout: BCC - Installation Guide.pdf
Cable Selection – Rated CurrentInstallation Conditions (3.3t) Handout: BCC - Installation Guide.pdf
Cable Selection – Rated CurrentNumber of Cables in a Conduit Handout: BCC - Installation Guide.pdf
Cable Selection – Multiple Conductors • To increase the rated current Handout: BCC - Installation Guide.pdf
Cable Selection – Multiple Conductors • Only for cable from 50 sq.mm. and up • Same type of cables • Same length • Same wiring method
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%
Cable Selection – Voltage Drop Zcable Zload 220 V (AC)
Cable Selection – Voltage Drop • Load: is from the consumption and power factor: or • Cable: is from the table ( and ) • depends on the wiring configurations.
Cable Selection – Voltage DropCalculation • 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
Cable Selection – Rated CurrentCalculation http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pour-visualisation_basse_def.pdf
Equivalent CircuitsImpedance: table for PVC cables and Electrical Systems Design: ประสิทธิ์ พิทยพัฒน์
Cable Selection – Rated CurrentFrom Table http://www.east-med.schneider-electric.com/documents/electrical-distribution/en/shared/eig_guide2010/Doc-pour-visualisation_basse_def.pdf
Cable Selection – General Rules • 20% to 25% factor. • Using current or VA (not power).
Cable Selection – Examples • Water Heater 6kW • in Air or in Metal Conduit • Microwave 2,300VA • Industrial Heater 40kW, 400V 3phase • 40oC or 50oC
Cable Selection – Examples • Motor 37kW, 400V, In=72A • DOL & Star-Delta • Motor 60kW, 400V, pf.=0.8 • Room • receptacles 2.5kVA • lighting 500VA
Handout • BCC - Installation Guide • HELUKABEL - Installation Operating Conditions • AS_NZS_3008.1.1_2009
Reference • Electrical Systems Design: ประสิทธิ์ 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