Date Code 20011026 Special Application Settings F-1
SEL-321/321-1 Instruction Manual
APPENDIX F: SPECIAL APPLICATION SETTINGS
Some settings have special values to actuate line specific features. These are documented in this
appendix.
VALUE OF “S” FOR E51N, E51Q
With typical settings of “Y” or “N”, the time overcurrent accumulation is blocked for a single-
pole open (SPO) condition. When E51N is set to “S”, SPO does not block the 51N elements.
When E51Q is set to “S”, SPO does not block the 51Q elements.
VALUE OF “N1” OR “Y1” FOR ESPT SETTING
N1 activates special Scheme 1 Trip Logic if the SPTE contact enables single-pole tripping.
Y1 activates special Scheme 1 Trip Logic equations:
Figure F.1: Scheme 1 Trip Decision Logic for Phase A
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