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Over head power lines
This document discusses transmission lines and overhead power lines. It describes different types of transmission lines like coaxial cable, microstrip, and twisted pair. It then covers overhead power lines, explaining that they transmit electricity over long distances using conductors like copper, steel, aluminum, and ACSR. The document also classifies overhead transmission lines by voltage and discusses conductor materials and their properties.
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Over head power lines
- 1. TRANSMISSION LINE • Whatis it? • Uses? • Practical Application? *Coaxial cable *Microstrip *Stripline *Balanced lines *Twisted pair *Star quad *Over-Head Trasnmission Line *Cables
- 2. OVER HEAD POWERLINES What are they? What are they used for? Materials? Use? Operating Voltages?
- 3. CLASSIFICATION OF OHTL Low Voltage <1000 volts Medium Voltage(Distribution) b/w 1kv-33kv High Voltage(subtransmission) <100 kv *Use? • Extra High Voltage Transmission >230 kv -800 kv • Ultra High Voltage Transmission >800 kv
- 6. CONDUCTOR A conductor isa material that facilitates the flow of electricity (or electric current) through a transmission line. • Copper • Steel • Aluminium • ACSR
- 7. COPPER • Abundantly available. •Excellent conductor. • Exist in three forms. i. Soft drawn ii. Medium drawn iii.Hard drawn
- 8. COPPER Soft-drawn copperconductors are commonly used in short transmission line spans and to ground electrical systems. They are flexible and resistant to breaking even under high stress. Medium-drawn copper conductors are used for medium-range distribution lines. Hard-drawn copper conductors are used in longer spans (greater than 200 feet) and are the strongest of the three. Their strength, however, makes them inflexible and often difficult to work with.
- 9. STEEL • Not mucheffective. • Rusts.(Due to which steel conductors are hardly used alone) • Steel conductors are commonly galvanized. (coated with a layer of zinc to counteract their rusting tendency) • Three to five times stronger than copper. conductors, and can be used for longer spans with fewer supports.
- 10. ALUMINIUM • Higher thermalexpansion.. • Lower strength. • Less than half the conductivity of copper.. • Light weight.(less sag) • Cheap. Aluminum conductors are commonly used for higher-voltage overhead transmission lines, power cables, busbars, motors, heating elements, heat sinks and foil windings.
- 11. ACSR CONDUCTOR • Steel-ReinforcedAluminium • Used in medium-, high- and extra-high-voltage (EHV) transmission lines. • High-strength • High-capacity • Exhibit excellent conductivity • Light weight(used in overhead transmission lines, river crossings and longer spans)
- 12. ACSR transmissionlines have a central steel strand, surrounded by outer aluminium strands. The steel conductor supports the weight of the transmission line while the aluminium is used for its conductive properties ACSR transmission cables are available in specific sizes and varying amounts of central steel strands as well as outer aluminium conductors
- 13. TYPES OF OHTLW.R.T CONSTRUCTION Bundle conductors Ground wires Insulated conductors Circuits
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- 18. FURTHER APPLICATIONS Used tosupply transmitting antennas For Train power