The document discusses the role of power cables in electrical power systems. It describes how cables are classified based on their application, such as for overhead transmission lines, power transmission, and underground cables. It also discusses factors that can cause trouble for cables, including mechanical activities, accessories, improper selection, overvoltages, and installation problems. Additionally, it covers the importance of earthing electrical systems and describes how well-designed earthing systems provide a safe return path for fault currents and minimize hazards.

1. Practical Power Cabling & Earthing
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2. Role of Power Cables in Electrical Power
Systems
• An electrical cable - A bundle of electrical conductors used for carrying
electricity
• Cables classification depends on their application
• Applications:
Electric cables
Overhead transmission lines
Power transmission
Overhead lines
Underground cables
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3. Role of Power Cables in Electrical Power
Systems
Typical view of an overhead transmission line terminating at a substation
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4. Role of Power Cables in Electrical Power
Systems
Typical view of a 33kV, cross-linked polyethylene cable
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5. Trouble-free Operation of Cables
• Trouble causing factors:
– Mechanical activities in the vicinity
– Accessories
– Improper selection of the cable
– Overvoltages arising from system operation or due
to external factors
– Installation problems causing excessive stresses
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6. Earthing and its Importance
A typical earth electrode used in electrical installations
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7. Earthing and its Importance
A metal chassis being used as earth reference
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8. Earthing
• Provides an electrical supply system with an
electrical reference to the earth mass
• Earthed metallic surface ensures that it stays at
earth potential always and thus remains safe to
persons who may come into contact with it
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9. Earthing and its Importance
(a) Fault in unearthed
system, (b) Effect of
earthing the neutral
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10. Fault current flow in a earthed system
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11. System Earthing and Protective
Earthing
• Well designed earthing systems:
• Provide a low impedance return path for earth fault currents back to the
power source so that the occurrence of fault can be sensed by the circuit
protective devices and faulty circuit can be safely isolated.
• Minimize fire or explosion hazard by providing an earth path of
adequate rating, matching the let through energy by circuit protective
devices.
• To dissipate accumulated static charges on machinery parts and
electronic assemblies containing sensitive circuits to avoid damage or
accidents
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12. DO YOU WANT TO KNOW MORE?
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