Setpoint Group - GE 889 Instruction Manual

CHAPTER 4: SETPOINTS

Setpoint Group

889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
The 889 relay provides six setpoint groups. All setpoints contained under the protection
setpoints are reproduced in six groups, identified as Setpoint Groups 1, 2, 3, 4, 5 and 6.
These multiple setpoints provide the capability for both automatic and manual switching
to protection settings for different operating situations. Automatic (adaptive) protection
setpoint adjustment is available to change settings when the power system configuration
is altered.
Automatic group selection can be initiated from the autoreclose, SETPOINT GROUPS and
by use of a SET GROUP x ACTIVE setpoint input. The group selection can be initiated by this
input from any FlexLogic operands, inputs, pushbuttons or communications.
Group 1 is the default for the "Active Group" and is used unless another group is requested
to become active. The active group can be selected with the ACTIVE SETPOINT GROUP
setpoint, by SET ACTIVE x GROUP input or inputs from autoreclose, SETPOINT GROUPS. If
there is a conflict in the selection of the active group, between a setpoint, inputs and inputs
from functions, the higher numbered group is made active. For example, if the inputs for
Group 2, 4, and 6 are all asserted the relay uses Group 6. If the logic input for Group 4 then
becomes de-asserted, the relay uses Group 3. Under some application conditions, the user
requires that the relay does not change from the present active group. This prevention of a
setpoint group change can be applied by setting Change Inhibit inputs (1 to 16). If needed,
typically this change inhibit is done when any of the overcurrent (phase, neutral, ground,
or negative sequence), overvoltage, bus or line undervoltage, or underfrequency elements
are picked-up.
Path:
Setpoints > Control > Setpoint Groups
ACTIVE SETPOINT GROUP
Range: 1,2,3,4,5,6
Default: 1
The Active Setpoint Group setting is used for manual selection of the Active Setpoint
Group by setting.
SET GROUP 2 (3,4,5,6) ACTIVE
Range: Off, Any FlexLogic operand
Default: Off
The setpoint selects the FlexLogic operand that initiates change of the Active Setpoint
Group.
GROUP CHANGE INHIBIT 1 (UP TO 16)
Range: Off, Any FlexLogic operand
Default: Off
The setpoint selects the FlexLogic operand that inhibits change of the active setpoint
group.
EVENTS
Range: Disabled, Enabled
Default: Enabled
CONTROL
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