Supervising Elements - GE UR Series Instruction Manual

5.5 GROUPED ELEMENTS
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PATH: SETTINGS GROUPED ELEMENTS
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SUPERVISING
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ELEMENTS
a) DISTURBANCE DETECTOR
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PATH: SETTINGS GROUPED ELEMENTS
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DISTURBANCE
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DETECTOR
5
The DD element is an 87L-dedicated sensitive current disturbance detector that is used to detect any disturbance on the
protected system. This detector is intended for such functions as; trip output supervision, VT and CT failure supervision,
starting oscillography data capture, and providing a continuous monitor feature to the relays.
If the disturbance detector is used to supervise the operation of the 87L function, it is recommended that the 87L TRIP logic
element be used. The 50DD SV disturbance detector FlexLogic™ output operand must then be assigned to an
setting.
SUPV
The DD function measures the magnitude of the negative sequence current (I_2), the magnitude of the zero sequence cur-
rent (I_0), the change in negative sequence current (∆I_2), the change in zero sequence current (∆I_0), and the change in
positive sequence current (∆I_1).
The DD element uses the same source of computing currents as that for the current differential scheme 87L.
The Adaptive Level Detector operates as follows:
• When the absolute level increases above 0.12 pu for I_0 or I_2, the Adaptive Level Detector output is active and the
next highest threshold level is increased 8 cycles later from 0.12 to 0.24 pu in steps of 0.02 pu. If the level exceeds
0.24 pu, the current Adaptive Level Detector setting remains at 0.24 pu and the output remains active (as well as the
DD output) when the measured value remains above the current setting.
• When the absolute level is decreasing from in range from 0.24 to 0.12 pu, the lower level is set every 8 cycles without
the Adaptive Level Detector active. Note that the 50DD output remains inactive during this change as long as the delta
change is less than 0.04 pu.
The Delta Level Detectors (∆I) detectors are designed to pickup for the 0.04 pu change in I_1, I_2, and I_0 currents. The ∆I
is measured by comparing the present value to the value calculated 4 cycles earlier.
DD FUNCTION:
This setting is used to Enable/Disable the operation of the Disturbance Detector.
DD NON-CURRENT SUPV:
This setting is used to select a FlexLogic™ operand which will activate the output of the Disturbance Detector upon events
(such as frequency or voltage change) not accompanied by a current change.
5-118
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SUPERVISING ELEMENTS

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DISTURBANCE
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DETECTOR
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OPEN POLE DETECTOR
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MESSAGE
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87L TRIP
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MESSAGE
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SUPERVISING ELEMENTS
DD
FUNCTION: Disabled
DD NON-CURRENT SUPV:
MESSAGE
Off
DD CONTROL LOGIC:
MESSAGE
Off
DD LOGIC SEAL-IN:
MESSAGE
Off
DD
MESSAGE
EVENTS: Disabled
L90 Line Differential Relay
5.5.21 SUPERVISING ELEMENTS
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DISTURBANCE DETECTOR
Range: Disabled, Enabled
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: FlexLogic™ operand
Range: Disabled, Enabled
GE Power Management
5 SETTINGS
87L TRIP