Cable arrangement
Cable arrangement
(OP)
Dear all experts,
I have a question regarding the 132kV underground cable arrangement. In commom practice, trefoil and flat formation are usually adopted in cable laying, but which one is better? What is their advantages and disadvantages?
Also, I have read a page talking about cable arrangement. It mentioned that VERTICAL ARRANGEMENT OF THREE PHASES CABLE MAY DERATE THE CABLE. What do they mean?
I have a question regarding the 132kV underground cable arrangement. In commom practice, trefoil and flat formation are usually adopted in cable laying, but which one is better? What is their advantages and disadvantages?
Also, I have read a page talking about cable arrangement. It mentioned that VERTICAL ARRANGEMENT OF THREE PHASES CABLE MAY DERATE THE CABLE. What do they mean?






RE: Cable arrangement
In a vertical arrangement, the lower cables will heat the upper cable leading to a derating of the upper cable (which implies a derating of all three cables).
RE: Cable arrangement
RE: Cable arrangement
All single core cables are preferably laid in trefoil formation. 132kV class cables I believe are necessarily single core cables.
This is because in trefoil formation the flux due to individual phase currents sums up to zero and thus leaving no residual flux externally that otherwise could link with the metal around the cables (such as trays, supporting metal or ducting) causing problems.