Date Code 990430 Factory-Set Logic 1-33
SEL-351P Manual Técnico
• An overcurrent trip is in progress (except SEF element trip)
• Either
of the following two scenarios is true:
− Ground trip precedence enabled and ground fault current above Min. trip - ground
level
− Ground trip precedence disabled, ground fault current above Min. trip - ground
level, and phase fault current below Min. trip - phase level
The SEL-351P is driven to lockout if all
the following are true:
• The number of trip operations is greater than or equal to setting Operations to lockout -
phase (Relay Word bit OLP asserted to logical 1)
• An overcurrent trip is in progress (except SEF element trip)
• Either of the following two scenarios is true:
− Ground trip precedence enabled, ground fault current below Min. trip - ground
level, and phase fault current above Min. trip - phase level
− Ground trip precedence disabled and phase fault current above Min. trip - phase
level
The SEL-351P is driven to lockout (regardless of the Ground trip precedence setting) if all
the
following are true:
• An overcurrent trip is in progress (except SEF element trip)
• The number of trip operations is greater than or equal to setting Operations to lockout -
ground (Relay Word bit OLG asserted to logical 1)
• The number of trip operations is greater than or equal to setting Operations to lockout -
phase (Relay Word bit OLP asserted to logical 1)
The SEL-351P is driven to lockout if both
the following are true:
• The SEF element trips
• The number of trip operations is greater than or equal to setting Operations to lockout -
SEF (Relay Word bit OLS asserted to logical 1)
High-Current Lockout
The controlling logic for the High-current lockout - phase and ground elements is found in
preceding
Figure SECTION 1: .17. The resultant High-current lockout - phase and High-current
lockout - ground elements are used in the drive-to-lockout logic in
Figure SECTION 1: .25. If
phase or ground fault current exceeds the pickups of either of these respective High-current
lockout - phase and High-current lockout - ground elements when the SEL-351P trips, the
SEL-351P is driven to lockout.
• If setting High current lockout - ground is set effectively below 0.1 Amp secondary,
67N1 operates as the High current lockout - ground element (67G1 is turned off
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