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Accessories are the vital links in the underground cable network. The term "accessories" refers to joints, termination, link boxes and Bonding Cables that form part of the cable network. Each type is briefly described below:

 

Termination

A termination is an accessory installed at both end of cable, where a cable gets connected to equipment such as a transformer or a switchgear or overhead lines. The design features of the termination should fulfill functional requirements of the termination which are given below:

  • Distribution of electrical field
  • Outer protection at different environmental conditions

Terminations or sealing ends are divided to four types:

  • Out door sealing end with porcelain insulator
  • Outdoor sealing end with Composite insulator-silicone rubber
  • SF6 (GIS) sealing end
  • Transformer sealing end

 

Joint

A joint is an accessory for jointing cables in the run of the cable circuit.

Functional requirements of the joint are given here under:

  • Distribution of electrical field Conductor
  • Outer mechanical protection
  • Corrosion protection
  • Water sealing protection
     

There are Three Main types of joints:

  • Straight - through joint
  • Cross- Bonding Joint

From the construction point of view joints are divided into the following categories:

  • Heat shrinkable Joint
  • Lapped Joints
  • Pre-molded Joint
  • Molded joint
  • Transient Joint

 

Link Boxes

Metallic sheath/ screen is connected to the ground by means of the insulated conductor through an enclosure termed as "Link Box" Link Box has an arrangement within to isolate the cable sheath/ screen from ground.

Following types of link boxes are used in EHV Cable installations:

  • Link Box with or without SVL (Surge Voltage Limiter)
  • Cross connected link box with or without SVL