GE Multilin
G30 Generator Protection System
6-21
6 ACTUAL VALUES
6.3 METERING
6
The metered frequency values are displayed in this menu. The "SRC 1" text will be replaced by whatever name was pro-
grammed by the user for the associated source (see
SETTINGS
SYSTEM SETUP
SIGNAL SOURCES
).
SOURCE FREQUENCY
is measured via software-implemented zero-crossing detection of an AC signal. The signal is either a
Clarke transformation of three-phase voltages or currents, auxiliary voltage, or ground current as per source configuration
(see the
SYSTEM SETUP
POWER SYSTEM
settings). The signal used for frequency estimation is low-pass filtered. The
final frequency measurement is passed through a validation filter that eliminates false readings due to signal distortions and
transients.
i) CURRENT HARMONICS AND THD METERING
PATH: ACTUAL VALUES
METERING
SOURCE SRC 1
CURRENT HARMONICS
The metered current harmonics values are displayed in this menu. The "SRC 1" text will be replaced by whatever name
was programmed by the user for the associated source (see
SETTINGS
SYSTEM SETUP
SIGNAL SOURCES
). Current
harmonics are measured for each source for the total harmonic distortion (THD) and 2nd to 25th harmonics per phase.
j) VOLTAGE HARMONICS AND THD METERING
PATH: ACTUAL VALUES
METERING
SOURCE SRC 1
VOLTAGE HARMONICS
The metered voltage harmonics values are displayed in this menu. The “SRC 1” text will be replaced by the programmed
name for the associated source (see the
SETTINGS
SYSTEM SETUP
SIGNAL SOURCES
menu).
To extract the 2nd to 25th voltage harmonics, each harmonic is computed on a per-phase basis, where:
N
= 64 is the number of samples per cycle
ω
0
= 2
π
f
is the angular frequency based on the system frequency (50 or 60 Hz)
k
= 1, 2,...,
N
– 1 is the index over one cycle for the Fast Fourier Transform (FFT)
m
is the last sample number for the sliding window
h
= 1, 2,..., 25 is the harmonic number
The short-time Fourier transform is applied to the unfiltered signal:
CURRENT HARMONICS
SRC 1
SRC 1
THD Ia: 0.0
Ib: 0.0
Ic: 0.0%
MESSAGE
SRC 1
2ND Ia: 0.0
Ib: 0.0
Ic: 0.0%
MESSAGE
SRC 1
3RD Ia: 0.0
Ib: 0.0
Ic: 0.0%
↓
MESSAGE
SRC 1 25TH Ia: 0.0
Ib: 0.0
Ic: 0.0%
VOLTAGE HARMONICS
SRC 1
SRC 1
THD Va: 0.0
Vb: 0.0
Vc: 0.0%
MESSAGE
SRC 1
2ND Va: 0.0
Vb: 0.0
Vc: 0.0%
MESSAGE
SRC 1
3RD Va: 0.0
Vb: 0.0
Vc: 0.0%
↓
MESSAGE
SRC 1 25TH Va: 0.0
Vb: 0.0
Vc: 0.0%
Содержание G30
Страница 10: ...x G30 Generator Protection System GE Multilin TABLE OF CONTENTS ...
Страница 30: ...1 20 G30 Generator Protection System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Страница 414: ...5 274 G30 Generator Protection System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Страница 456: ...8 2 G30 Generator Protection System GE Multilin 8 1 DIRECTIONAL PRINCIPLE 8 THEORY OF OPERATION 8 ...
Страница 470: ...9 14 G30 Generator Protection System GE Multilin 9 1 SETTING EXAMPLE 9 APPLICATION OF SETTINGS 9 ...
Страница 484: ...11 12 G30 Generator Protection System GE Multilin 11 6 DISPOSAL 11 MAINTENANCE 11 ...
Страница 512: ...A 28 G30 Generator Protection System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Страница 620: ...B 108 G30 Generator Protection System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Страница 666: ...E 10 G30 Generator Protection System GE Multilin E 1 IEC 60870 5 104 APPENDIX E E ...
Страница 678: ...F 12 G30 Generator Protection System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...
Страница 687: ...GE Multilin G30 Generator Protection System H 7 APPENDIX H H 2 ABBREVIATIONS H Z Impedance Zone ...