PF9800 Series User's Manual
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©
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20
component to that of the fundamental (the 1st order). The computation equations are
as follows:
%
100
U
)
U
(
thd
U
1
n
2
k
2
k
×
=
∑
=
or
%
100
I
)
I
(
thd
I
1
n
2
k
2
k
×
=
∑
=
%
100
U
U
U
1
k
k%
×
=
or
%
100
I
I
I
1
k
k%
×
=
CSA method(
)
：
Computes the ratio of the rms value of the 2nd to 50th order component to that of the
rms value the 1st to 50th component. The computation equation are as follows:
%
100
)
U
(
)
U
(
thd
U
n
1
k
2
k
n
2
k
2
k
×
=
∑
∑
=
=
or
%
100
)
I
(
)
I
(
thd
I
n
1
k
2
k
n
2
k
2
k
×
=
∑
∑
=
=
%
100
)
U
(
U
U
n
1
k
2
k
k
k%
×
=
∑
=
or
%
100
)
I
(
I
I
n
1
k
2
k
k
k%
×
=
∑
=
Where Uthd or Ithd: the total harmonic distortion of voltage or current
U1 or I1
：
the effective value of
fundamental
frequency (the first
harmonic) of voltage or current;
Uk or Ik
：
the effective value of kth harmonic of
voltage or current;
Uk% or Ik%
：
the relative value of kth harmonic of
voltage or current;
k
：
harmonic order;
n
：
the maximum harmonic order set by user,n=50.
(2) Calculation method of total harmonic voltage, current and power
Total harmonic voltage
：
∑
=
=
Σ
n
1
k
2
k
)
U
(
U
Total harmonic current
：
∑
=
=
Σ
n
1
k
2
k
)
I
(
I
