GE Multilin
L90 Line Current Differential System
9-51
9 THEORY OF OPERATION
9.6 FAULT LOCATOR
9
(EQ 9.53)
For two-terminal applications, the following equalities hold for the above equation.
(EQ 9.54)
For two-terminal applications, the distance is reported from the local relay. In three-terminal applications, the distance is
reported from the terminal of a given line segment.
Phase rotation must be the same at all line terminals for correct operation of the multi-ended fault locator.
b) EXAMPLE
Consider a three-terminal, 500 kV application with no charging current compensation or zero-sequence removal. The
phase rotation is ABC and the following CT and VT data is known.
The tap settings are shown below.
The primary positive-sequence impedances and length for the line are shown below.
The three relays are connected as shown below.
Table 9–31: CT AND VT APPLICATION DATA FOR MULTI-ENDED EXAMPLE
VALUE
RELAY 1
RELAY 2
RELAY 3
CT primary
1200 A
1000 A
1600 A
CT secondary
5 A
1 A
5 A
VT connection
wye
delta
wye
VT secondary
57.73 V
83.33 V
57.73 V
VT ratio
5000:1
6000:1
5000:1
Table 9–32: TAP SETTINGS MULTI-ENDED EXAMPLE
VALUE
RELAY 1
RELAY 2
RELAY 3
CT tap 1 for remote terminal 1
1000 / 1200 = 0.8333
1200 / 1000 = 1.200
1200 / 1600 = 0.750
CT tap 1 for remote terminal 2
1600 / 1200 = 1.3333
1600 / 1000 = 1.600
1000 / 1600 = 0.625
Table 9–33: LINE LENGTH AND POSITIVE-SEQUENCE IMPEDANCE FOR MULTI-ENDED EXAMPLE
VALUE
RELAY 1 TO TAP
RELAY 2 TO TAP
RELAY 3 TO TAP
Impedance
21.29
80.5°
36.50
80.5°
16.73
80.5°
Length
70 km
120 km
55 km
D
pu
Re
V
1
X
V
TAP X
Z
----------------------------------------
I
TAP X
I
FLT X
-----------------------------------------------------------------
D
units
D
pu
L
V
1
X
V
LOC X
V
TAP X
V
REM
1
X
I
TAP X
I
REM
1
X
I
FLT X
I
LOC X
I
REM
1
X
NOTE
Summary of Contents for UR Series L90
Page 652: ...A 16 L90 Line Current Differential System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 772: ...B 120 L90 Line Current Differential System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Page 802: ...C 30 L90 Line Current Differential System GE Multilin C 7 LOGICAL NODES APPENDIX C C ...
Page 812: ...D 10 L90 Line Current Differential System GE Multilin D 1 IEC 60870 5 104 APPENDIX D D ...
Page 824: ...E 12 L90 Line Current Differential System GE Multilin E 2 DNP POINT LISTS APPENDIX E E ...
Page 834: ...F 10 L90 Line Current Differential System GE Multilin F 3 WARRANTY APPENDIX F F ...
Page 846: ...xii L90 Line Current Differential System GE Multilin INDEX ...
