PQC Series
Static Var Generator
46
Wherein:
L
max
is
the maximum one-way wiring length from the CT to the system cabinet (m);
P
CT
is
the nominal secondary capacity of the CT (VA);
P1
is
the capacity loss and the internal impedance of the system cabinet
(each module’s internal loss is around 2 VA);
I
is the secondary current of the CT (A);
S
is the cross-section area of the copper conductor (mm
2
);
ρ
is the resistivity of the copper conductor
(calculated according to 0.0178
Ω
× m/ mm
2
);
Table 3-3: Lmax and Cross-section Area When CT Secondary Current is 5A and
under Single Module System
Cross-
section
Area of
the
Conductor
Lmax
15VA CT
20VA CT
25VA CT
30VA CT
35VA CT
40VA CT
2.5 mm
2
36 m
50 m
64 m
78 m
92 m
106 m
4 mm
2
58 m
80 m
103 m
125 m
148 m
157 m
3.6.2 Basic CT Installation & Wiring
•
The CT for current detection shall be located on either grid side or load side
•
When it’s an open loop, the CT for current detection shall be located on the load side
to feed the detection signal to the SVG as shown in
Figure 3-27
. When it’s a close
loop, the CT for current detection shall be located on the grid side to feed the detection
signal to the SVG as shown in
Figure 3-28
.
•
A set of three CTs must be provided for current detection in an imbalance load.
•
The CTs shall be oriented accurately. The default is that P1 is placed toward the grid.
And the direction of all
CTs must be the same.
•
The phase sequences of the detection signal of the CTs must not be changed.
