Control - GE 845 Instruction Manual

CONTROL

Control
Setpoint Group
4–298
Figure 4-122: Control Display Hierarchy
Level 1
The 845 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.
Device
Setpoint Group
System
Local Control Mode
Inputs
Breaker Control Data Capture
Outputs
Switch Control Data Capture
Protection
Virtual Input Control Data Capture
Monitoring
Trip Bus
Control
Breaker Failure
FlexLogic
Arc Flash
Testing
Synchrocheck
VT Fuse Failure
Level 2 Level 3
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 4: SETPOINTS
BF Setup
BF Initiate
Level 4