CHAPTER 4: SETPOINTS CONTROL889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–333Setpoint GroupThe 889 relay provides six setpoint groups. All setpoints contained under the protectionsetpoints 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 switchingto protection settings for different operating situations. Automatic (adaptive) protectionsetpoint adjustment is available to change settings when the power system configurationis altered.Automatic group selection can be initiated from the autoreclose, SETPOINT GROUPS andby use of a SET GROUP x ACTIVE setpoint input. The group selection can be initiated by thisinput from any FlexLogic operands, inputs, pushbuttons or communications.Group 1 is the default for the "Active Group" and is used unless another group is requestedto become active. The active group can be selected with the ACTIVE SETPOINT GROUPsetpoint, by SET ACTIVE x GROUP input or inputs from autoreclose, SETPOINT GROUPS. Ifthere is a conflict in the selection of the active group, between a setpoint, inputs and inputsfrom functions, the higher numbered group is made active. For example, if the inputs forGroup 2, 4, and 6 are all asserted the relay uses Group 6. If the logic input for Group 4 thenbecomes de-asserted, the relay uses Group 3. Under some application conditions, the userrequires that the relay does not change from the present active group. This prevention of asetpoint 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 elementsare picked-up.Path: Setpoints > Control > Setpoint GroupsACTIVE SETPOINT GROUPRange: 1,2,3,4,5,6Default: 1The Active Setpoint Group setting is used for manual selection of the Active SetpointGroup by setting.SET GROUP 2 (3,4,5,6) ACTIVERange: Off, Any FlexLogic operandDefault: OffThe setpoint selects the FlexLogic operand that initiates change of the Active SetpointGroup.GROUP CHANGE INHIBIT 1 (UP TO 16)Range: Off, Any FlexLogic operandDefault: OffThe setpoint selects the FlexLogic operand that inhibits change of the active setpointgroup.EVENTSRange: Disabled, EnabledDefault: Enabled
