CHAPTER 7: PROTECTION
GROUPED PROTECTION ELEMENTS
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
271
Source
Range: LINE (SRC 1), BKR 1 (SRC 2), BKR 2 (SRC 3)
Default: LINE (SRC 1)
This setting selects the signal source for the auxiliary undervoltage protection element.
Pickup
Range: 0.000 to 3.000 pu in steps of 0.001
Default: 0.700 pu
This setting specifies the auxiliary undervoltage pickup level in per-unit values.
Curve
Range: Definite Time, Inverse Time
Default: Inverse Time
This setting selects either the desired time-delay operating characteristic versus the
applied fundamental voltage or the definite time characteristic for the auxiliary
undervoltage element.
Delay
Range: 0.00 to 600.00 seconds in steps of 0.01
Default: 1.00 seconds
This setting selects the minimum operating time of the auxiliary undervoltage element.
Minimum Voltage
Range: 0.000 to 3.000 pu in steps of 0.001
Default: 0.100 pu
This setting specifies the operating voltage below which the auxiliary undervoltage
element is blocked.
Block
Range: any FlexLogic™ operand or shared operand
Default: Off
Assertion of the operand assigned to this setting blocks the auxiliary undervoltage
element.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of auxiliary undervoltage events in the
sequence of events recorder.
The logic for the auxiliary undervoltage element is shown below. The logic is identical for all
auxiliary undervoltage elements.
Figure 233: Auxiliary undervoltage scheme logic
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