Should the 10kV busbar be equipped with a power supply PT

Yes, the busbar PT should generally be put into operation before energizing the 10kV power supply to ensure accurate metering, protection, and safety interlocks.Operational Sequence and RationaleBusbar potential transformers (PTs) are critical for providing voltage signals to protection relays, metering devices, and control systems. If the PT is not in operation before closing the 10kV circuit breaker, several issues can arise:Incorrect Metering and Protection Signals: Without the PT energized, relays and meters may interpret the busbar as de-energized, potentially causing false trips or misoperation of protection devices .Safety Interlocks: Many substations implement interlocks that prevent closing the busbar breaker unless the PT is in the correct operational position. This prevents accidental energization of the busbar without proper voltage sensing .Risk of PT Damage: Racking in or energizing a PT while the busbar is already live can lead to flashover or explosion due to even small primary currents, especially if the PT is not designed for on-load switching .Best PracticesFollow Design Documentation: The original designer and commissioning engineer specify the correct sequence. Interlocks are installed for a reason and should not be bypassed .Energize PT First: Ensure the PT is in the operational position and connected to the busbar before closing the 10kV breaker. This ensures that all protection and metering devices receive accurate voltage signals.Check Interlocks: Verify that all mechanical and electrical interlocks are functioning correctly to prevent unsafe operations.Commissioning Verification: During commissioning, confirm that the PT and busbar protection operate as intended under simulated fault and normal conditions .SummaryPutting the busbar PT into operation before energizing the 10kV supply is essential for safety, accurate protection, and reliable metering. Interlocks are typically designed to enforce this sequence, and bypassing them can compromise system stability and personnel safety. Always consult the original design and commissioning documentation for the specific substation or power plant.