Schweitzer Engineering SEL-351P, Быстрый старт

Страница: 62 / 674

Settings
56 SEL-351P Quick-Start Installation and User's Guide (Portuguese)
Setting Default Range Incr.
Cold load pickup - ground OFF OFF, 1.00-79.99 multiples of Min.
trip - ground 0.01
The Cold load pickup - ground setting determines the ground current threshold for overcurrent
detection when the Cold load pickup scheme is active (also applied to SEF element as the SEF current
threshold for overcurrent detection).
Example: If Cold load pickup - ground = 1.50 (multiples of Min. trip - ground ), Min. trip -
ground (No. 6) = 50.00 Amps primary, and the cold load pickup scheme is active, then the
ground current threshold for overcurrent detection operates at a value equal to:
1.50
•
50.00 Amps primary = 75.00 Amps primary
The SEF current threshold for overcurrent detection also operates at a value equal to 75 Amps primary
when the cold load pickup scheme is active.
The upper limit of this setting (80.00 multiples) is calculated from the Amps secondary range upper
limit [20] and settings
CT Ratio (No. 3) [200.0] and Min. trip - ground (No. 6) [50.00]:
(20
•
200.0)/50.00 = 80.00 multiples (upper limit)
Due to processor calculations and rounding techniques, displayed range numbers may appear slightly
different than expected (e.g., 79.99 instead of 80.00).
•
If Cold load pickup - ground is set to OFF, then the ground current threshold for overcurrent
detection remains unchanged (threshold remains equal to setting Min. trip - ground [No. 6]) and
the SEF current threshold for overcurrent detection remains unchanged (threshold remains equal
to setting
Min. trip - SEF [No. 7]).
•
This setting is hidden and set to OFF if Cold load pickup scheme is set to N or Delay curve -
ground (No. 11) is set to OFF.
Setting Default Range Incr.
Loss of load diversity time 0.00 0-999999.00 cycles 0.25 cyc.
The Loss of load diversity timer starts to time if both the following are true:
•
The recloser is open.
•
The control is in the lockout state or reclosing is defeated.
When the Loss of load diversity timer times out, the cold load pickup scheme is activated, causing the
following to occur:
•
Fast curves are disabled.
•
Delay curves and SEF element are desensitized per preceding cold load pickup settings (the
curves are not shifted - coordination is maintained).
When the recloser is closed, the cold load pickup scheme remains active. If the recloser remains
closed, the current thresholds for overcurrent detection return naturally to their regular
Min. trip (No.
5, 6, or 7) levels when the inrush current goes below these respective regular levels for at least 15
seconds. The respective fast curves are enabled again. This return to normal conditions is separate for
phase, ground, and SEF elements (e.g., ground could return to normal before phase or SEF, depending
on the subsidence rates of inrush currents).
•
This setting is hidden and set to zero (0) if Cold load pickup scheme is set to N.