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If 10% error doesn’t conform to the requirements, the general measures taken are:
Increasing the section area of the secondary cable area (decreasing the secondary
impedance)
Connecting the current transformers of the same type and transformation ratio in series
(reducing the excitation current of the transformer)
Using the winding with high excitation characteristic (increasing the excitation impedance)
Increasing the transformation ratio of the current transformer (increasing the excitation
impedance)
Figure 40
Error curve calculation formula:
M =
(
I*P
)
/N
ZII =
(
U-
(
I*Z2
))
/(K*I)
I Current
U Voltage
N=1 (1A Rating Current )
I Current
N=5 (5A Current)
Z2 CT Secondary Side Impedance
P=20
(
5%Error Curve
)
K=19
(
5%Error Curve. 1A 5A Rating Current
)
P=10
(
Error Curve
)
K=9
(
10%Error Curve. A 5A Rating Current
)
Содержание ZXHQ-A+ CT
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