5-238
L30 Line Current Differential System
GE Multilin
5.9 TRANSDUCER INPUTS AND OUTPUTS
5 SETTINGS
5
(EQ 5.34)
The base unit for current (refer to the
FlexElements
section in this chapter for additional details) is:
(EQ 5.35)
The minimum and maximum power values to be monitored (in pu) are:
(EQ 5.36)
The following settings should be entered:
DCMA OUTPUT H2 SOURCE
: “SRC 1 Ia RMS”
DCMA OUTPUT H2 RANGE
: “4 to 20 mA”
DCMA OUTPUT H2 MIN VAL
: “0.000 pu”
DCMA OUTPUT H2 MAX VAL
: “1.260 pu”
The worst-case error for this application could be calculated by superimposing the following two sources of error:
•
±0.5% of the full scale for the analog output module, or
•
±0.25% of reading or ±0.1% of rated (whichever is greater) for currents between 0.1 and 2.0 of nominal
For example, at the reading of 4.2 kA, the worst-case error is max(0.0025
4.2 kA, 0.001
5 kA) + 0.504 kA = 0.515 kA.
EXAMPLE: VOLTAGE MONITORING
A positive-sequence voltage on a 400 kV system measured via source 2 is to be monitored by the dcmA H3 output with a
range of 0 to 1 mA. The VT secondary setting is 66.4 V, the VT ratio setting is 6024, and the VT connection setting is
“Delta”. The voltage should be monitored in the range from 70% to 110% of nominal.
The minimum and maximum positive-sequence voltages to be monitored are:
(EQ 5.37)
The base unit for voltage (refer to the
FlexElements
section in this chapter for additional details) is:
(EQ 5.38)
The minimum and maximum voltage values to be monitored (in pu) are:
(EQ 5.39)
The following settings should be entered:
DCMA OUTPUT H3 SOURCE
: “SRC 2 V_1 mag”
DCMA OUTPUT H3 RANGE
: “0 to 1 mA”
DCMA OUTPUT H3 MIN VAL
: “0.404 pu”
DCMA OUTPUT H3 MAX VAL
: “0.635 pu”
The limit settings differ from the expected 0.7 pu and 1.1 pu because the relay calculates the positive-sequence quantities
scaled to the phase-to-ground voltages, even if the VTs are connected in “Delta” (refer to the
Metering conventions
section
in chapter 6), while at the same time the VT nominal voltage is 1 pu for the settings. Consequently the settings required in
this example differ from naturally expected by the factor of
.
The worst-case error for this application could be calculated by superimposing the following two sources of error:
•
±0.5% of the full scale for the analog output module, or
•
±0.5% of reading
For example, under nominal conditions, the positive-sequence reads 230.94 kV and the worst-case error is
0.005 x 230.94 kV + 1.27 kV = 2.42 kV.
I
max
1.5 4.2 kA
6.3 kA
=
=
I
BASE
5 kA
=
minimum current
0 kA
5 kA
------------
0 pu, maximum current
6.3 kA
5 kA
-----------------
1.26 pu
=
=
=
=
0.005
20 4
–
6.3 kA
0.504 kA
=
V
min
0.7
400 kV
3
-------------------
161.66 kV,
V
max
1.1
400 kV
3
-------------------
254.03 kV
=
=
=
=
V
BASE
0.0664 kV 6024
400 kV
=
=
minimum voltage
161.66 kV
400 kV
---------------------------
0.404 pu, maximum voltage
254.03 kV
400 kV
---------------------------
0.635 pu
=
=
=
=
3
0.005
1 0
–
254.03 kV
1.27 kV
=
Summary of Contents for L30
Page 10: ...x L30 Line Current Differential System GE Multilin TABLE OF CONTENTS ...
Page 30: ...1 20 L30 Line Current Differential System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Page 370: ...5 244 L30 Line Current Differential System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 464: ...A 10 L30 Line Current Differential System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 600: ...C 30 L30 Line Current Differential System GE Multilin C 7 LOGICAL NODES APPENDIX C C ...
Page 610: ...D 10 L30 Line Current Differential System GE Multilin D 1 IEC 60870 5 104 APPENDIX D D ...
Page 622: ...E 12 L30 Line Current Differential System GE Multilin E 2 DNP POINT LISTS APPENDIX E E ...
Page 634: ...F 12 L30 Line Current Differential System GE Multilin F 3 WARRANTY APPENDIX F F ...
Page 644: ...x L30 Line Current Differential System GE Multilin INDEX ...
