Upper Boat — 275 kV Cable Design
275 kV Full cable design including bonding, joints and route
The challenge
The client needed a complete 275 kV cable design package to support a design and installation project as part of a key substation upgrade. Aurora was tasked with optimising the route design and cable size and advising on the most suitable bonding technique.
What Aurora did
We delivered a complete 275 kV cable design package covering current rating calculations, sheath voltage calculations, bonding scheme design, pulling force calculations, joint bay drawings and cable route layout drawings. The bonding scheme was the key design issue, because it directly affected sheath voltage during faults, induced voltage during normal operation and the protection arrangement to be agreed with the connecting party. Additional challenges included optimising the HDD section depth to keep cable thermal ratings within limits and confirming acceptable pulling forces along the final route.