Define a tie-bus breaker.
The Correct Answer and Explanation is:
Correct Answer:
A tie-bus breaker is a circuit breaker that connects two separate busbars (or bus sections) in a substation, allowing them to operate together or independently for flexibility, reliability, and maintenance purposes.
In electrical power systems, substations often use multiple busbars to distribute power reliably and flexibly. A tie-bus breaker is a circuit breaker installed between two busbars (also called a tie-breaker or bus coupler), enabling operational configurations such as splitting, paralleling, or transferring loads between bus sections.
The main function of a tie-bus breaker is to enhance the reliability and maintainability of the power distribution system. By linking two busbars, it allows the system to maintain power delivery even when one bus needs to be taken offline for maintenance or in the event of a fault. For example, if Bus A is feeding several loads and needs to be de-energized, the tie-bus breaker can be closed to transfer the load to Bus B, ensuring continuous supply.
In normal operation, the tie-breaker may remain open, keeping the two buses isolated. However, under specific operational needs, it can be closed to share the load, balance voltages, or isolate faults. This capability significantly increases the flexibility of the power system.
Tie-bus breakers also play a crucial role in fault isolation and system protection. In case of a fault in one bus, opening the tie-bus breaker can prevent the fault from propagating to the adjacent bus section, thus limiting outages.
Substation schemes such as double busbar, main and transfer bus, or one-and-a-half breaker designs often include tie-bus breakers to maximize reliability and operational versatility.
In summary, the tie-bus breaker is a vital element in modern substations, enabling operational flexibility, load management, and enhanced reliability in the distribution of electrical power
