Small busbars in high-voltage switchgear are typically located within the branch sections, connecting circuit breakers, disconnectors, and instrument transformers to the main busbars.

Placement in HV Switchgear

In high-voltage switchgear, small busbars are usually found in the branch compartments rather than the main busbar compartment. They serve to connect incoming and outgoing circuit breakers, branch disconnectors, and instrument transformers to the main busbars, enabling controlled distribution of electrical energy to each branch circuit . These busbars are often insulated or enclosed to ensure safety and prevent short circuits, especially in compact switchgear designs .

Types and Support

Small busbars can be flat, tubular, or laminated, depending on the design requirements. They are supported by insulators (commonly ceramic) and connected to equipment terminals using appropriate connectors, such as bronze for copper-copper connections or bi-metallic connectors for copper-aluminum interfaces . In some designs, flexible busbars are used to accommodate movement or vibration near circuit breakers, while rigid busbars are used for stable connections within the branch .

Function and Safety Considerations

These busbars ensure that current is safely distributed from the main bus to each branch while maintaining mechanical stability and electrical insulation. In high-voltage installations, small busbars are often enclosed in metallic or ventilated compartments to protect personnel and reduce the risk of electrical faults, while still allowing adequate cooling . Their location within the branch compartment allows for maintenance and sectionalizing without interrupting the entire switchgear operation . In summary, small busbars are positioned in the branch sections of HV switchgear, connecting the main busbars to circuit breakers, disconnectors, and transformers, and are designed with insulation, support, and safety measures appropriate for high-voltage operation .