What is a trip bypass, and under what circumstances might it be used in core protection?

• A. Permanent disabling of protective action.
• B. Planned maintenance windows that disable protection without formal authorization.
• C. A temporary disabling of protective action under controlled conditions (e.g., maintenance) with authorization and risk assessment; restored after.
• D. A software patch to modify protection logic.

Answer: (C)

A trip bypass is a controlled, temporary disabling of a protective action to allow maintenance or testing to proceed without triggering automatic trips. It must have explicit authorization and a documented risk assessment, and it is limited in time and scope. The protection is restored after the work is completed and the system is verified to be ready again.

In practice, this means engineers and operators agree on a defined window during which the protective action can be bypassed, implement the bypass with proper surveillance and signaling, and re-enable the protection once the task is finished. This keeps work moving while still maintaining safety controls, and it prevents permanent removal of protections or unapproved changes.

The other notions don’t fit because permanent disabling would defeat safety, performing maintenance without formal authorization bypasses required controls, and a software patch changes protection logic rather than providing a temporary, authorized exception for a specific job.