GE Power Management
750/760 Feeder Management Relay 14-
1
14 S7 CONTROL 14.1 SETPOINT GROUPS
14
14 S7 CONTROL 14.1 SETPOINT GROUPS 14.1.1 DESCRIPTION
All setpoints contained under page
S5 PROTECTION
are reproduced in four groups, identified as Groups 1, 2, 3
and 4. These multiple setpoints provide the capability of both automatic and manual changes to protection set-
tings for different operating situations. Automatic (adaptive) protection setpoint adjustment is available to
change settings when the power system configuration is altered. By monitoring the state of a bus tie breaker
on the bus connected to the associated feeder breaker, you may use different settings depending on whether
the tie breaker is open or closed. Automatic group selection can be initiated by use of a logic input. The manual
adjustment capability is available for those users who use different settings for different seasons of the year.
Manual group selection can be initiated from the keypad or via communications.
In order to allow the display and editing of one group while another group is used for protection, two operating
states have been assigned to setpoint groups. The 'Active' group is used for protection, and is indicated by the
appropriate faceplate LED indicator being turned on continuously. The 'Edit' group is displayed and may be
used to alter protection settings. It is indicated by the appropriate faceplate LED indicator being flashed. If a
single group is selected to be both the Active and Edit group, the appropriate indicator is on continuously.
The setpoint group to be edited can only be selected by setpoint. Group 1 is the default for the active group
and will be used unless another group is requested to become active. The group to become active can be
selected by setpoint or by logic input. If there is a conflict in the selection of the active group, between a set-
point and logic input or between two logic inputs, the higher numbered group will be made active. For example,
if the logic inputs for group 2, 3, and 4 are all asserted the relay would use group 4. If the logic input for group
4 then becomes de-asserted, the relay will use group 3. Any change from the default group 1 will be stored in
the event recorder.
In some application conditions, the user may require that the relay will not change from the present active
group. This prevention of a setpoint group change can be applied when any of the overcurrent (phase, neutral,
ground, sensitive ground, or negative sequence), overvoltage, bus or line undervoltage, or underfrequency ele-
ments are picked-up.
Pickup of a protection element is possible when selected to any function except ‘Disabled’, so ele-
ments that are not used to perform tripping can also inhibit setpoint changes. A setting change can
also be prevented if the breaker is open, so that a fault detected before a reclosure will not cause a
group change while the breaker is open.
Each set
oint
rou
includes the selection of out
ut rela
s 3-7 AUXILIARY that can be o
er-
ated b
the
rotection features. As these rela
s are hard-wired to external e
ui
ment, the
selection should onl
be chan
ed from that in Set
oint Grou
1 with considerable care.
NOTE
CAUTION
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