Circutor AFQm-3WF-030M-480, Инструкция по эксплуатации

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42
AFQm
Instruction Manual
harmonics measured in the load by a
safety factor
(
FS
h
). In other words:
I
FiLTER
(AFQm) = [FS
h
* I
LOaD
* THD(I)]
Where:
I
FILTER
(AFQm) : rated current of the active filter.
FS
h
: safety factor > 1.2.
I
LOAD
: maximum current of the load.
THD(I)
: harmonic distortion of the load current.
Equation 6:Rated current of the AFQm�
To calculate this
safety factor
you must first know the parameter called
short-circuit ratio R
SC
, at the
connection point of the PCL transducers (not on the installation input). The short-circuit ratio is de-
fined as the ratio between the short-circuit current of a mains (
I
SC
) and the rated current of the set of
non-linear transducers ( I
CNL
) producing the harmonics to be filtered.
(
Equation 7
)
𝑈𝑈
𝑛𝑛
% =
𝑈𝑈
𝑛𝑛
𝑈𝑈
1
∗ 100
𝐼𝐼
𝑛𝑛
% =
𝐼𝐼
𝑛𝑛
𝐼𝐼
1
∗ 100
𝑈𝑈 =
�𝑈𝑈
1
2
+ 𝑈𝑈
2
2
+ 𝑈𝑈
3
2
+ 𝑈𝑈
5
2
+ ⋯
𝐼𝐼 =
�𝐼𝐼
1
2
+ 𝐼𝐼
2
2
+ 𝐼𝐼
3
2
+ 𝐼𝐼
5
2
+ ⋯
𝑇𝑇𝑇𝑇𝑇𝑇 ( 𝑈𝑈 )% =
�𝑈𝑈
2
2
+ 𝑈𝑈
3
2
+ 𝑈𝑈
5
2
+ ⋯
𝑈𝑈
1
𝑇𝑇𝑇𝑇𝑇𝑇
(
𝐼𝐼
)% =
�𝐼𝐼
2
2
+ 𝐼𝐼
3
2
+ 𝐼𝐼
5
2
+ ⋯
𝐼𝐼
1
𝐼𝐼
𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹
= 𝐼𝐼
𝐹𝐹𝑅𝑅𝑅𝑅
− 𝐼𝐼
𝐶𝐶𝐶𝐶𝐹𝐹𝐶𝐶𝐶𝐶
𝐼𝐼
𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹𝐹
(
𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴
) = [
𝐴𝐴𝐹𝐹
ℎ
∗ 𝐼𝐼
𝐶𝐶𝐶𝐶𝐹𝐹𝐶𝐶𝐶𝐶
∗ 𝑇𝑇𝑇𝑇𝑇𝑇 ( 𝐼𝐼 )]
𝑅𝑅
𝑆𝑆𝐶𝐶
=
𝐼𝐼
𝑆𝑆𝐶𝐶
𝐼𝐼
𝐶𝐶𝐶𝐶𝐹𝐹
Equation 7:Calculating the short-circuit ratio R
SC
�
In a real installation, the short-circuit current (
I
SC
) in the PCL can be assessed by having the voltage at
the said point for two different load currents.
For example, full load, I
A
and 10% load, I
B
. If V
OC
is the rated voltage at no-load, the I
SC
, can be calculated
using the formula shown in
Figure 35
:
Figure 35:Graph for calculating I
SC
�
The safety factor ( FS
h
) can be obtained from the graph in
Figure 36
: