GE F60 Instruction Manual page 534

METERING
6.4.2.10 Current harmonics and THD metering
ACTUAL VALUES  METERING  SOURCE SRC 1  CURRENT HARMONICS
 CURRENT HARMONICS
 SRC 1
This menu displays metered current harmonics values. The "SRC 1" text is replaced by the name was programmed for the
associated source (see
for the total harmonic distortion (THD) and 2nd to 25th harmonics per phase.
6.4.2.11 Voltage harmonics and THD metering
ACTUAL VALUES  METERING  SOURCE SRC 1  VOLTAGE HARMONICS
 VOLTAGE HARMONICS
 SRC 1
6
This menu displays metered voltage harmonics values. The "SRC 1" text is replaced by the programmed name for the
associated source (see the
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 = 2πf is the angular frequency based on the system frequency (50 or 60 Hz)
0
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:
The harmonics are a percentage of the fundamental signal obtained as a ratio of harmonic amplitude to fundamental
amplitude multiplied by 100%. The total harmonic distortion (THD) is the ratio of the total harmonic content to the
fundamental:
6-22
SRC 1 THD Ia: 0.0

Ib: 0.0 Ic: 0.0%
SRC 1 2ND Ia: 0.0

Ib: 0.0 Ic: 0.0%
SRC 1 3RD Ia: 0.0

Ib: 0.0 Ic: 0.0%
SRC 1 25TH Ia: 0.0

Ib: 0.0 Ic: 0.0%
SETTINGS  SYSTEM SETUP  SIGNAL SOURCES
SRC 1 THD Va: 0.0

Vb: 0.0 Vc: 0.0%
SRC 1 2ND Va: 0.0

Vb: 0.0 Vc: 0.0%
SRC 1 3RD Va: 0.0

Vb: 0.0 Vc: 0.0%
SRC 1 25TH Va: 0.0

Vb: 0.0 Vc: 0.0%
SETTINGS  SYSTEM SETUP  SIGNAL SOURCES

). Current harmonics are measured for each source

menu).
F60 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 6: ACTUAL VALUES
Eq. 6-3
Eq. 6-4