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889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
FLEXLOGIC
CHAPTER 4: SETPOINTS
Path:
Setpoints > FlexLogic > FlexElements > FlexElement 1
FUNCTION
Range: Disabled, Enabled
Default: Disabled
NAME
Range: Up to 13 alphanumeric characters
Default: FlexEl 1
INPUT 1 (+)
Range: Off, any FlexAnalog signal
Default: Off
This setting specifies the first input (non-inverted) to the FlexElement. Zero is assumed
as the input if this setting is set to “Off”. For proper operation of the element at least one
input must be selected. Otherwise, the element will not assert its output operands.
INPUT 2 (-)
Range: Off, any FlexAnalog signal
Default: Off
This setting specifies the second input (inverted) to the FlexElement. Zero is assumed as
the input if this setting is set to “Off”. For proper operation of the element at least one
input must be selected. Otherwise, the element will not assert its output operands.
This input should be used to invert the signal if needed for convenience, or to make the
element respond to a differential signal such as for a top-bottom oil temperature
differential alarm.
A warning message is displayed and the element does not operate if the two input
signals are of different types, for example if one tries to use active power and phase
angle to build the effective operating signal.
PICKUP
Range: -30.000 to 30.000 pu in steps of 0.001 pu
Default: 1.000
This setting specifies the operating threshold for the effective operating signal of the
element.
If the “Over” direction is set, the element picks up when the operating signal exceeds the
PICKUP value.
If the “Under” direction is set, the element picks up when the operating signal falls below
the PICKUP value.
The HYSTERESIS setting controls the element drop out.
Notice that both the operating signal and the pickup threshold can be negative when
facilitating applications such as reverse power alarms.
The FlexElement can be programmed to work with all analog values measured or
computed by the relay. The PICKUP setting is entered in pu values using the following
definitions of the base units:
Table 4-40: Definitions of the Base Unit for the FLEXELEMENT
Measured or calculated analog
value related to:
Base Unit
Voltage
V
BASE
= maximum nominal primary RMS value of the Input
1(+) and input 2(-) inputs
Current
I
BASE
= maximum nominal primary RMS value of the Input 1(+)
and input 2(-) inputs
Power
P
BASE
= maximum value of V
BASE
* I
BASE
for the Input 1(+) and
input 2(-) inputs
Power Factor
PF
BASE
= 1.00
