41
Instruction Manual
AFQevo
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 defined as the ratio between the short-circuit current of a main (
I
SC
) and the nominal
current of the set of non-linear transducers (
I
CNL
) producing the harmonics to be filtered.
(
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 6: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 33:Graph for calculating I
SC
�
The safety factor (
FS
h
) can be obtained from the graph in
Figure 34:Approximate graph for calculating the FS
h
�
