GE Multilin
B90 Low Impedance Bus Differential System
6-9
6 ACTUAL VALUES
6.3 METERING
6
6.3METERING
6.3.1 METERING CONVENTIONS
a) UR CONVENTION FOR MEASURING PHASE ANGLES
All phasors calculated by UR-series relays and used for protection, control and metering functions are rotating phasors that
maintain the correct phase angle relationships with each other at all times.
For display and oscillography purposes, all phasor angles in a given relay are referred to an AC input channel pre-selected
by the
SETTINGS
SYSTEM SETUP
POWER SYSTEM
FREQUENCY AND PHASE REFERENCE
setting. This setting
defines a particular AC signal source to be used as the reference.
If the AC signal pre-selected by the relay upon configuration is not measurable, the phase angles are not referenced. The
phase angles are assigned as positive in the leading direction, and are presented as negative in the lagging direction, to
more closely align with power system metering conventions. This is illustrated below.
Figure 6–1: UR PHASE ANGLE MEASUREMENT CONVENTION
6.3.2 BUS ZONE
PATH: ACTUAL VALUES
METERING
BUS
BUS ZONE 1(4)
These values display the differential and restraint currents phasors for each bus zone. The magnitudes are displayed in pri-
mary amperes (see chapter 8:
Theory of operation
for additional details).
There is no cutoff level applied to the differential and restraint currents computed by the B90. Therefore, a small dif-
ferential current reflecting CT inaccuracies and bus leakage current could be present during balanced conditions.
This is done to achieve a more accurate differential balance and provide the user a direct indication of the real dif-
ferential current, as excluding small currents or not accounting for CT errors may impose significant unaccounted
differential current. It is advisable to set the minimum pickup for 87B protection greater than the maximum differen-
tial current during normal load conditions.
BUS ZONE 1
BUS ZONE 1 DIFF:
0.000 A 0.0°
MESSAGE
BUS ZONE 1 REST:
0.000 A 0.0°
827845A1.CDR
UR phase angle
reference
0
o
-45
o
-90
o
-135
o
-270
o
-225
o
-180
o
-315
o
positive
angle
direction
NOTE
Содержание B90 UR Series
Страница 28: ...1 20 B90 Low Impedance Bus Differential System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Страница 114: ...4 28 B90 Low Impedance Bus Differential System GE Multilin 4 3 FACEPLATE INTERFACE 4 HUMAN INTERFACES 4 ...
Страница 272: ...6 14 B90 Low Impedance Bus Differential System GE Multilin 6 5 PRODUCT INFORMATION 6 ACTUAL VALUES 6 ...
Страница 316: ...A 4 B90 Low Impedance Bus Differential System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Страница 406: ...B 90 B90 Low Impedance Bus Differential System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Страница 436: ...C 30 B90 Low Impedance Bus Differential System GE Multilin C 7 LOGICAL NODES APPENDIX C C ...
Страница 446: ...D 10 B90 Low Impedance Bus Differential System GE Multilin D 1 IEC 60870 5 104 APPENDIX D D ...
