Schweitzer Engineering SEL-351P - Page 121

Date Code 990215 Factory-Set Logic 1-25
SEL-351P Manual Técnico
Other overcurrent element enable/disable details involving ground and SEF elements:
• See
Figure SECTION 1: .16 (bottom) and Figure SECTION 1: .18. If setting Cold
load pickup - ground is set effectively below 0.05 Amp secondary, 50N5 is set to this
Cold load pickup - ground value (50G5 is turned off automatically). 50N5 provides the
effective Min. trip - ground for Delay curve - ground when the cold load pickup scheme
is actively engaged (similar to
Figure SECTION 1: .5). Otherwise, 50G5 provides the
effective Min. trip - ground for Delay curve - ground when the cold load pickup scheme
is actively engaged (50N5 is turned off automatically).
• See
Figure SECTION 1: .18. The SEF element is enabled only if none of the Fast
curve and Delay curve elements are picked up and timing. If the SEF element is used, it
is traditionally set to be more sensitive than any other overcurrent elements.
Cold load pickup scheme
actively engaged for phase
(see Figure 1.2)
Cold load pickup scheme
not active for phase
and
Fast curve -
phase enabled
Enable fast curve - phase
(see Figure 1.6)
Cold load pickup scheme
not active for ground
and
Cold load pickup scheme
actively engaged for ground
(see Figure 1.3)
TERRA HABILITADO
operator control ON
(see Figure 1.37)
51N1TC
Torque
Control
SEL
OGIC
Settings
51P1TC
Input into
51P1T logic
(see Figure
3.14)
DWG: MP351P013
Rela
y
Word
Bits
SV8
OCP
SV10
LT1
Enable fast curve - ground
(see Figure 1.7)
OCG
51G1TC
Input into
51N1T logic
(see Figure
3.16)
Input into
51G1T logic
(see Figure
3.18)
Fast curve -
ground enabled
Figure SECTION 1: .15: Fast Curve - Phase (top) and Fast Curve - Ground (bottom)
Enable/Disable Logic