Case Study:
VMAG 25kV Circuit Breaker Replacement on the East Coast Mainline
Client:
Babcock Rail / Network Rail
Project
Partner:
WJ Project Services
Location:
East Coast Mainline – York Area
Scope:
VMAG 25kV circuit breaker installation, HV equipment testing, Level A/B switching, cross-boundary feeder commissioning
WJ Project Services was commissioned to upgrade ageing high-voltage circuit breakers across key substations in the York area following deterioration of insulation levels within existing switchgear. The programme focused on improving system integrity, reliability, and long-term operational safety.
Works included isolation and earthing activities, removal of legacy HVCBs, and installation of new HSS VMAG 25kV circuit breakers, through-wall bushings, voltage transformers, and isolators. Detailed switching schedules were developed to allow phased changeovers while maintaining alternate feeding arrangements.
Comprehensive testing was undertaken, including SCADA end-to-end verification, pressure and wiring tests, ductor testing, interlocking checks, function testing, and cross-boundary National Grid feeder testing. Entry into service procedures were completed in accordance with Network Rail standards
HSS VMAG 25kV vacuum circuit breakers and associated HV interface wiring infrastructure were installed, providing enhanced insulation performance, improved reliability, and modernised protection capability.
The project delivered fully renewed and commissioned HV circuit breaker systems, strengthening feeder station resilience and ensuring safe, reliable operation across the East Coast Mainline.
