7.4.5 Harmonic Measurement (/G5 Option)
Item Specifications
Measured item All installed elements
Method PLL synchronization method
Frequency range Fundamental frequency of the PLL source is in the range of 10 Hz to 1.2 kHz.
PLL source •
Select voltage or current of each input element.
• Input level
50% or more of the rated measurement range when the crest factor is 3.
100% or more of the rated measurement range when the crest factor is 6.
•
The frequency filter must be turned on when the fundamental frequency is less than or equal to 200Hz.
FFT
data length
1024
Window function Rectangular
Sample rate, window width, and upper limit of harmonic analysis
Fundamental Frequency Sample Rate Window Width Upper Limit of Harmonic Analysis*
10 Hz to 75 Hz f×1024 1 50
75 Hz to 150 Hz f×512 2 32
150 Hz to 300 Hz f×256 4 16
300 Hz to 600 Hz f×128 8 8
600 Hz to 1200 Hz f×64 16 4
f in the equation is the input fundamental frequency.
* The upper limit of harmonic order can be decreased.
Accuracy
(The accuracy shown below is the sum of reading and range errors.)
When Line Filter is OFF
<WT310/WT332/WT333>
Frequency Voltage Current Power
10Hz≤f<45Hz 0.15% of reading
+0.35% of range
0.15% of reading
+0.35% of range
0.35% of reading
+0.50% of range
45
Hz≤
f≤440Hz 0.15% of reading
+0.35% of range
0.15% of reading
+0.35% of range
0.25% of reading
+0.50% of range
440
Hz<
f≤1kHz 0.20% of reading
+0.35% of range
0.20% of reading
+0.35% of range
0.40% of reading
+0.50% of range
1
kHz<
f≤2.5kHz 0.80%+ of reading
+0.45% of range
0.80%+ of reading
+0.45% of range
1.56% of reading
+0.60% of range
2.5
kHz<
f≤5kHz 3.05% of reading
+0.45% of range
3.05% of reading
+0.45% of range
5.77% of reading
+0.60% of range
<WT310HC>
Frequency Voltage Current Power
10Hz≤f<45Hz 0.15% of reading
+0.35% of range
0.15% of reading
+0.35% of range
0.35% of reading
+0.50% of range
45
Hz≤
f≤440Hz 0.15% of reading
+0.35% of range
0.15% of reading
+0.35% of range
0.25% of reading
+0.50% of range
440Hz<
f≤1kHz 0.20% of reading
+0.35% of range
0.20% of reading
+0.35% of range
0.40% of reading
+0.50% of range
1
kHz<
f≤2.5kHz 0.80%+ of reading
+0.45% of range
0.95%+ of reading
+0.45% of range
1.68% of reading
+0.60% of range
2.5
kHz<
f≤5kHz 3.05% of reading
+0.45% of range
3.35% of reading
+0.45% of range
6.05% of reading
+0.60% of range
•
When the crest factor is set to 3.
• Whenλ
(thepowerfactor)is1.
• Power figures that exceed 1.2 kHz are reference values.
• Foradirectcurrentrange,add10μAtothecurrentaccuracyand(10μv/directcurrentrange)×100%ofrangetothepower
accuracy.
• Fortheexternalcurrentsensorrange,add100μAtothecurrentaccuracyand(100μV/externalcurrentsensorrangerating)×
100% of range to the power accuracy.
• For nth harmonic component input, add ({n/(m + 1)}/50)% of (the nth harmonic reading) to the n + mth harmonic and n – mth
harmonic of the voltage and current, and add ({n/(m + 1)}/25)% of (the nth harmonic reading) to the n + mth harmonic and n –
mth harmonic of the power.
•
Add (n/500)% of reading to the nth component of the voltage and current, and add (n/250)% of reading to the nth component
of the power
.
•
The accuracy when the crest factor is 6 is the same as the accuracy when the crest factor is 3 after doubling the measurement
range.
•
The guaranteed accuracy ranges for frequency
, voltage, and current, are the same as the guaranteed ranges for ordinary
measurement. If the amplitude of the high frequency component is large, influence of approximately 1% may appear in certain
harmonics. Because the influence depends on the size of the frequency component, if the frequency component is small with
respect to the range rating, the influence is also negligible.
7.4 Features
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