Planning

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Dimensioning a short circuit-resistant cable system

A cable system includes the following components:

  • Cable
  • Cable terminations
  • Cable joints
  • Cable Clamps
  • Mounting hardware
  • Cable racks
  • Support systems

Each individual component must be capable to safely control the dynamic forces which occur during a short circuit.

The following factors should be considered when designing a cable support system:

  • Peak short circuit current ip (kA)
  • Sustained short circuit current i"K (kA)
  • Operating voltage UN (kV)
  • Cable type, cable design, sectional view and maximum permitted deflection of the cable
  • Maximum outer diameter of the cable (m)
  • For single cable routing, the centre-to-centre distance of the cables (m)
  • Distance between Cable Clamps (m)
  • Length of the cable route (m)
  • Dynamic short circuit resistance of the Cable Clamp (N)
  • Dynamic resistance to short circuits of the substructure and of the fastening material (N)

Suitable separation between Cable Clamps depends on:

  • Peak short circuit current
  • Dynamic short circuit resistance of the Cable Clamp
  • Cable design, including bending stiffness (bending modulus).

During short circuit events, sharp deflections of the cable must be avoided. If the maximum deflection of the cable is exceeded, it can be irreparably damaged and require complete replacement, including re-installation of the entire cable system.

 

A Blackout of Only One Hour Causes in Germany Costs of Nearly 600 Million Euro.

(Study of the Hamburg Institut of International Economics [HWWI]) Piaszeck, S. et el (2013). Regional Diversity in the Costs of Electricity Outages: Results for German Counties.HWWI Research Paper, 2013 (142), p. 16-30