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5-182
L60 Line Phase Comparison System
GE Multilin
5.5 GROUPED ELEMENTS
5 SETTINGS
5
The positive-sequence restraint must be considered when testing for pick-up accuracy and response time (multiple of
pickup). The operating quantity depends on the way the test currents are injected into the relay:
•
Single-phase injection:
I
op
= 1/3
×
(1 –
K
) ×
I
injected
.
•
Three-phase pure zero- or negative-sequence injection, respectively:
I
op
=
I
injected
.
•
The directional unit uses the negative-sequence current and voltage for fault direction discrimination.
The following table defines the negative-sequence directional overcurrent element.
The negative-sequence voltage must be higher than the
PRODUCT SETUP
ÖØ
DISPLAY PROPERTIES
ÖØ
VOLTAGE CUT-OFF
LEVEL
value to be validated for use as a polarizing signal. If the polarizing signal is not validated neither forward nor reverse
indication is given. The following figure explains the usage of the voltage polarized directional unit of the element.
The figure below shows the phase angle comparator characteristics for a phase A to ground fault, with settings of:
ECA
= 75° (element characteristic angle = centerline of operating characteristic)
FWD LA
= 80° (forward limit angle = ± the angular limit with the ECA for operation)
REV LA
= 80° (reverse limit angle = ± the angular limit with the ECA for operation)
The element incorporates a current reversal logic: if the reverse direction is indicated for at least 1.25 of a power system
cycle, the prospective forward indication will be delayed by 1.5 of a power system cycle. The element is designed to emu-
late an electromechanical directional device. Larger operating and polarizing signals will result in faster directional discrimi-
nation bringing more security to the element operation.
Figure 5–97: NEGATIVE-SEQUENCE DIRECTIONAL CHARACTERISTIC
The forward-looking function is designed to be more secure as compared to the reverse-looking function, and therefore
should be used for the tripping direction. The reverse-looking function is designed to be faster as compared to the forward-
looking function and should be used for the blocking direction. This allows for better protection coordination. The above
bias should be taken into account when using the negative-sequence directional overcurrent element to directionalize other
protection elements.
OVERCURRENT UNIT
DIRECTIONAL UNIT
MODE
OPERATING CURRENT
DIRECTION
COMPARED PHASORS
Negative-sequence
I
op
= |I_2| – K
×
I_1|
Forward
–V_2
+
Z_offset
×
I_2
I_2
×
1
∠
ECA
Reverse
–V_2
+
Z_offset
×
I_2
–(I_2
×
1
∠
ECA)
Zero-sequence
I
op
= |I_0| – K
×
|I_1|
Forward
–V_2
+
Z_offset
×
I_2
I_2
×
1
∠
ECA
Reverse
–V_2
+
Z_offset
×
I_2
–(I_2
×
1
∠
ECA)
827806A2.CDR
VAG (reference)
VCG
VBG
–I_2 line
I_2 line
ECA line
–ECA line
LA
LA
LA
LA
ECA
FWD Operating
Region
REV Operating
Region
FWD
LA
FWD
LA
REV
LA
REV
LA
V_2 line
–V_2 line
Summary of Contents for UR series
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Page 12: ...xii L60 Line Phase Comparison System GE Multilin TABLE OF CONTENTS ...
Page 32: ...1 20 L60 Line Phase Comparison System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Page 54: ...2 22 L60 Line Phase Comparison System GE Multilin 2 2 SPECIFICATIONS 2 PRODUCT DESCRIPTION 2 ...
Page 438: ...7 8 L60 Line Phase Comparison System GE Multilin 7 2 TARGETS 7 COMMANDS AND TARGETS 7 ...
Page 478: ...8 40 L60 Line Phase Comparison System GE Multilin 8 3 FAULT LOCATOR 8 THEORY OF OPERATION 8 ...
Page 502: ...A 10 L60 Line Phase Comparison System GE Multilin A 1 PARAMETER LIST APPENDIXA A ...
Page 584: ...B 82 L60 Line Phase Comparison System GE Multilin B 4 MEMORY MAPPING APPENDIXB B ...
Page 622: ...D 10 L60 Line Phase Comparison System GE Multilin D 1 PROTOCOL APPENDIXD D ...
Page 634: ...E 12 L60 Line Phase Comparison System GE Multilin E 2 DNP POINT LISTS APPENDIXE E ...
Page 642: ...F 8 L60 Line Phase Comparison System GE Multilin F 3 WARRANTY APPENDIXF F ...