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Underground Cables

Types of Cable Faults

Types of Cable Faults: Cables are generally laid directly in the ground or in ducts in the underground distribution system. For this reason, there are little chances of faults in underground cables. However, if a fault does occur, it is difficult to locate and repair the fault because conductors are not visible. Nevertheless, the following …

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Grading of Cables

Grading of Cables: The process of achieving uniform electrostatic stress in the dielectric of cables is known as grading of cables. It has already been shown that electrostatic stress in a single core cable has a maximum value (gmax) at the conductor surface and goes on decreasing as we move towards the sheath. The maxi­mum …

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Laying of Underground Cables

Laying of Underground Cables: The reliability of Laying of Underground Cables network depends to a considerable extent upon the proper laying and attachment of fittings i.e., cable end boxes, joints, branch connectors etc. There are three main methods of Laying of Underground Cables viz., Direct laying, Draw-in system and the Solid system. 1.Direct laying: This …

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Three Phase Service Cable

Three Phase Service Cable: In practice, underground cables are generally required to deliver 3-phase power. For the purpose, either three-core cable or three single core cables may be used. For voltages upto 66 kV, 3-core cable multi-core construction) is preferred due to economic reasons. However, for voltages beyond 66 kV, 3-core-cables become too large and …

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Classification of Underground Cables

Classification of Underground Cables: Classification of Underground Cables may be in two ways according to the type of insulating material used in their manufacture the voltage for which they are manufactured. However, the latter method of Classification of Underground Cables is generally preferred, according to which cables can be divided into the following groups : …

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Insulating Materials for Underground Cables

Insulating Materials for Underground Cables: The satisfactory operation of a cable depends to a great extent upon the characteristics of insulation used. Therefore, the proper choice of Insulating Materials for Underground Cables is of considerable importance. In general, the insulating materials used in cables should have the following properties : High insulation resistance to avoid …

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