288
D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CONTROL ELEMENTS
CHAPTER 7: PROTECTION
In this equation,
m
is a multiplier defined by the multiplier setting,
S
ref
represents the
pickup setting, and
S
op
represents the operating power at the time. This timer starts after
the definite time timer expires.
The four FlexCurves allow for custom user-programmable time characteristics. When
working with FlexCurves, the element uses the operate to pickup ratio, and the multiplier
setting is not applied:
Eq. 39
Again, the FlexCurve timer starts after the definite time timer expires.
Multiplier
Range: 0.01 to 2.00 seconds in steps of 0.01
Default: 1.00 seconds
This setting is applicable if the wattmetric
Curve
setting is “Inverse” and defines the
multiplier factor for the inverse time delay.
Block
Range: any FlexLogic™ operand
Default: Off
Assertion of the FlexLogic™ operand assigned to this setting blocks operation of the
wattmetric zero-sequence directional ground fault element.
Events
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the logging of wattmetric zero-sequence directional
ground fault events in the sequence of events recorder.
The logic for the wattmetric zero-sequence directional ground fault 1 element is shown
below. The logic is identical for both wattmetric elements.
Figure 247: Wattmetric zero-sequence directional ground fault logic
Control elements
Control elements are generally used for control rather than protection.
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