Outdoor HV disconnector: application scenarios and maintenance

Outdoor 27.5 kV disconnectors are used at sectioning posts, substation feeders, depots and crossovers where a visible isolation point is required.

• Sectioning posts — isolate one side of the OCS for maintenance; usually motorized for remote operation.
• Substation feeders — separate the feeder from the catenary; interlocked with the breaker.
• Depots and yards — provide visible isolation for staff working on the roof.
• Crossovers and bridging — allow transfer between tracks without de-energizing the whole section.

Maintenance points for outdoor units: clean pollution from insulators before the rainy season; check the anti-corrosion coating of the frame; verify the heater and sealing of the motor box; confirm the mechanical position indicator and remote signal agree; after a short-circuit, inspect contacts and the operating rod for deformation.