3C Teck Cable Shield Ground

[ZeroSeq]

Hello,

Recommended practices and calculations for cable shield grounding and induced voltages are readily available for single conductor cables. However, I'm finding a difficult time in finding a similar reference or standard for 3-Conductor or trefoil cable arrangement (e.g. Teck). Does anyone have a reference for the shield grounding for these types of cables?

 

[RRaghunath]

3-core cables do not pose any concern with regard to shield currents as all the three phases are within the same cable and thus there is no resultant flux (the three fluxes balance out) that can link the shield.
Trefoil formation for single core cables is to limit the flux that can link the structures nearby. But, as long as individual cable shield is concerned, there will be circulating current in case the shield is earthed at both ends of the cable. If earthed at only one end, the potential rise of the shield terminal at unearthed end needs to be calculated during normal load as well as during through faults and protected with SVLs.