Conclusion; Calculation; The Va Burden Of Our Svg Module; Ct Special Application Installation - Sinexcel SVG 100 Ultra User Manual

CONCLUSION

For the CT with the CT burden ≥ 5VA
If CT cable＜15m, 2.5mm^2, dual twisted pair CT cable is suggested.
If CT cable＞15m but＜30m, 4mm^2, dual twisted pair CT cable is suggested.
If CT cable＞30m, it is necessary to confirm whether the CT rated load is larger than the cable impedance.

CALCULATION

For the impedance calculation of the CT cable, please refer to the following calculation of the 100m CT
cable.
L
R 

S
For example, calculate the CT cable impedance by below formula
R: the impedance of cable

: copper resistivity L: cable length
S: cross-sectional area

L=100m, S=4mm , =0.0172Ω·mm
2
so R=0.43
So one round of CT cable impedance is 2*R=0.86Ω
The secondary side current of CT is 5A, but in fact the current should be less than 3.9A, otherwise SVG
will show alarm because of SVG software setting.
R  3.9 * 0.86  13.08VA
P  I 2 2
So
Since the CT is short-circuit inside the SVG, so the impedance of SVG could be neglected.
Base on the calculation, as long as the CT burden is bigger than 13.08VA, then SVG could worknormally.

THE VA BURDEN OF OUR SVG MODULE

Same as before calculation.
For our SVG/SVG module, L=20mm, S=2.5mm
R  3.9 * 2.8X10
P  I 2 2
So

CT SPECIAL APPLICATION INSTALLATION

When doing both harmonic mitigation and reactive power compensation with SVG and SVG equipment,
please notice that SVG installation point should be closer to the Load side than SVG as below figure shows.
/m,
2

2
  4.3X10
-4 3 V.
89
=0.0172Ω·mm 2 /m, So R=1.4X10 -4 -4
Ω，2R=2.8X10 Ω