GE Multilin
G60 Generator Protection System
6-21
6 ACTUAL VALUES
6.3 METERING
6
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:
(EQ 6.3)
The harmonics are a percentage of the fundamental signal obtained as a ratio of harmonic amplitude to fundamental ampli-
tude multiplied by 100%. The total harmonic distortion (THD) is the ratio of the total harmonic content to the fundamental:
(EQ 6.4)
Voltage harmonics are calculated only for Wye connected phase VTs. Ensure the
SYSTEM SETUP
AC INPUTS
VOLTAGE BANK F5
PHASE VT XX CONNECTION
setting is “Wye” to enable voltage harmonics metering.
6.3.4 SYNCHROCHECK
PATH: ACTUAL VALUES
METERING
SYNCHROCHECK
SYNCHROCHECK 1(4)
If a synchrocheck function setting is "Disabled", the corresponding actual values menu item is not displayed.
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%
SYNCHROCHECK 1
SYNCHROCHECK 1 DELTA
VOLT: 0.000
V
MESSAGE
SYNCHROCHECK 1 DELTA
PHASE: 0.0°
MESSAGE
SYNCHROCHECK 1 DELTA
FREQ: 0.00
Hz
F
real
m h
,
(
)
2
N
----
f m k
–
(
)
h
ω
0
t k
( )
⋅
⋅
(
)
cos
⋅
(
)
k
=
F
imag
m h
,
(
)
2
N
----
f m k
–
(
)
h
ω
0
t k
( )
⋅
⋅
(
)
sin
⋅
(
)
k
=
F
ampl
m h
,
(
)
F
real
m h
,
(
)
2
F
imag
m h
,
(
)
2
+
=
THD
F
2
2
F
3
2
…
F
25
2
+
+
+
=
NOTE
Summary of Contents for Multilin g60
Page 10: ...x G60 Generator Protection System GE Multilin TABLE OF CONTENTS INDEX ...
Page 32: ...1 22 G60 Generator Protection System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Page 160: ...4 30 G60 Generator Protection System GE Multilin 4 3 FACEPLATE INTERFACE 4 HUMAN INTERFACES 4 ...
Page 486: ...5 326 G60 Generator Protection System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 518: ...6 32 G60 Generator Protection System GE Multilin 6 5 PRODUCT INFORMATION 6 ACTUAL VALUES 6 ...
Page 532: ...7 14 G60 Generator Protection System GE Multilin 7 2 TARGETS 7 COMMANDS AND TARGETS 7 ...
Page 748: ...D 10 G60 Generator Protection System GE Multilin D 1 IEC 60870 5 104 APPENDIX D D ...
Page 760: ...E 12 G60 Generator Protection System GE Multilin E 2 DNP POINT LISTS APPENDIX E E ...