When Sellafield Ltd identified a fault within an 11kV transformer termination box, the root cause was traced to a void in the pitch insulation. To investigate and resolve the issue, the pitch-filled box was carefully melted out. Upon inspection, the existing PILC (Paper Insulated Lead Covered) cable was found to be in good condition and suitable for continued use.
The challenge lay in preserving the integrity of the aging PILC cable while ensuring its safe and reliable long-term performance. To address this, engineers at Sellafield collaborated with Stephen Davies of Lovink Enertech, drawing on the company’s deep expertise in advanced cable insulation technologies.
Together, it was decided to replace the traditional bitumen insulation with LoviSil®, a liquid silicone insulation medium developed by Lovink Enertech. Used in cable accessories for over 30 years, LoviSil® is known for its exceptional electrical and insulating properties.
A proven insulation upgrade
The restoration process involved thoroughly cleaning the termination box to remove any residual grease or bitumen. Once cleaned, the box was refilled with LoviSil® liquid insulation, offering several key benefits:
- Improved insulation performance: LoviSil® enhances the dielectric strength of the termination, reducing the likelihood of future faults.
- Preservation of paper insulation: The liquid medium prevents the paper layers in the PILC cable from drying out, extending the cable’s service life.
- Reduced risk of Partial Discharge: Because LoviSil® remains in liquid form, it eliminates air pockets that could lead to partial discharge.
- Higher breakdown resistance: Compared to mineral or synthetic oils, LoviSil® offers superior breakdown voltage, providing a more robust and reliable insulation barrier.
A sustainable solution for legacy infrastructure
This innovative approach allowed Engineers at Sellafield Ltd to restore the transformer termination without replacing the PILC cable, preserving valuable infrastructure while enhancing reliability. The use of LoviSil® demonstrates how modern insulation technologies can be effectively applied to legacy systems, ensuring continued safe operation and long-term performance.
Interesting facts
- LoviSil® insulation: more than just for cable joints
- Sustainable solution in termination boxes – replacement of GPLK cables unnecessary