Simulation Studies to Improve Design for Midlife 275 kV Cable Refurbishment

Simulation studies to reduce the number of link positions on an existing 275 kV cable route due for refurbishment are presented. This reduction in the number of link positions will effectively reduce the overall cost of maintenance and will also improve reliability. It is shown that the proposed layout and bonding arrangement can produce sheath voltages of up to 200 V during load conditions, 3 kV during extemal faults, and 6.4 kV during intemal faults. Transient sheath to ground voltages of up to 100 kVp during lightning and up to 95 kVp during faults can be experienced. These voltages will be acceptable in normal service. The capital efficiency of the refurbishment, which reduces the number of link positions, should also reduce the risks of subsequent failure and the cost of maintenance.