Use of the small busbar on the top of the high-voltage intermediate switchgear

The small busbar on top of HV/MV switchgear should be connected using properly rated rigid or flexible conductors, supported with insulated brackets, and coordinated with the main bus and circuit breakers to ensure safe, reliable power distribution.

Key Steps for Connection

1. Identify Busbar Type and Rating Determine whether the small busbar is rigid, flat, tubular, or laminated, and confirm its current rating, voltage class, and short-circuit capacity. This ensures the busbar can safely carry the intended load without overheating or mechanical stress . 2. Mechanical Support and Alignment Install insulated supports or brackets to maintain proper spacing from other busbars and grounded surfaces. Ensure the busbar is level and aligned with the connection points on the circuit breakers or incoming/outgoing feeders. Proper support prevents vibration, sagging, and potential insulation failure . 3. Electrical Connection

• Use bolted connections with torque values specified by the manufacturer to ensure low-resistance contact.
• If flexibility is required (e.g., for draw-out breakers), use flexible braided copper connectors to accommodate movement while maintaining electrical continuity .
• Ensure the busbar is properly phased and connected according to the single-line diagram of the switchgear, considering whether it is part of a single bus, double bus, or bypass bus configuration . 4. Insulation and Clearance Maintain adequate clearance from other live parts and grounded surfaces according to the voltage class. Use insulating barriers or sleeves where necessary to prevent accidental contact and flashover . 5. Coordination with Protection Devices Verify that the small busbar connection does not compromise circuit breaker operation, earthing switches, or bus couplers. In double bus or bypass configurations, ensure the busbar allows sectionalizing and maintenance without interrupting supply . 6. Testing and Verification After installation, perform:
• Continuity checks to confirm low-resistance connections.
• Insulation resistance tests to ensure no leakage paths.
• Visual inspection for proper alignment, torque, and support .

Safety Considerations

• Always de-energize the switchgear before connecting the busbar.
• Follow local electrical codes and manufacturer instructions.
• Use personal protective equipment (PPE) suitable for high-voltage work.
• Ensure earthing switches are engaged during installation to prevent accidental energization . By following these steps, the small busbar can be safely and reliably integrated into the high-voltage intermediate-voltage switchgear, maintaining operational flexibility and minimizing the risk of faults or downtime.