GE 845 User Manual

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

GE 845 Specifications

General

Brand	GE
Model	845
Category	Protection Device
Language	English