Synchrocheck - GE L30 Instruction Manual

CHAPTER 6: ACTUAL VALUES
6.4.3.9 Voltage harmonics and THD metering
ACTUAL VALUES  METERING  SOURCE SRC 1  VOLTAGE HARMONICS
 VOLTAGE HARMONICS
 SRC 1
This menu displays metered voltage harmonics values. The "SRC 1" text is replaced by the programmed name for the
associated source (see the
SETTINGS  SYSTEM SETUP  SIGNAL SOURCES
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:
Voltage harmonics are calculated only for Wye connected phase VTs. Ensure that the
 VOLTAGE BANK F5  PHASE VT XX CONNECTION

6.4.4 Synchrocheck

ACTUAL VALUES  METERING  SYNCHROCHECK  SYNCHROCHECK 1(4)
 SYNCHROCHECK 1

L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
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%
setting is "Wye" to enable voltage harmonics metering.
SYNCHROCHECK 1 DELTA

VOLT: 0.000 kV
SYNCHROCHECK 1 DELTA

FREQ: 0.00 Hz
SYNCHROCHECK 1

DELTA PHASE: 0.0°
SYNCHROCHECK 1

SYNSCP D_PH: 0.0°
menu).
SYSTEM SETUP  AC INPUTS
METERING
Eq. 6-3
6
Eq. 6-4
6-21