YOKOGAWA WT3002E User Manual page 157

9.1 IEC Harmonic Measurement Function
When the fundamental signal is 50 Hz
9-2
In IEC harmonic measurement, this instrument performs Fourier transform on the input
signal and divides the signal into frequency components as follows:
• Interharmonics
If the input signal is 50 Hz, 10 periods of the waveform are divided in 5-Hz resolution.
Thus, the section between each harmonic order is divided into 10 sections. The
components between each harmonic order are called interharmonics.
Rms component
Fundamental
dc 50
nd
2 harmonic
100
If the input signal is 60 Hz, 12 periods of the waveform are divided in 5-Hz resolution.
Thus, the section between each harmonic order is divided into 12 sections.
When the fundamental signal is 60 Hz
Rms component
Fundamental
dc 60
nd rd
2 harmonic 3 harmonic
100 150
rd
3
Interharmonics
nd
2 harmonic
120
th th
4 harmonic 5 harmonic
200 250
harmonic
150
rd th
3 harmonic 4 harmonic
180 240
Frequency [Hz]
Frequency [Hz]
IM WT3001E-51EN