For other voltages or conditions not included in the table, the value of C/K can be obtained by
means of a simple calculation.
Calculating the C/K Factor
The equation for calculating the C/K factor is:
where Ic: is the smallest capacitor current.
K: the current transformer transformation ratio.
To calculate Ic it is necessary to know the reactive power of the smallest capacitor Q and the
network voltage V.
The transformation ratio K is calculated as:
where Iprim : is the nominal current of the transformer primary.
Isec: is the current of the transformer secondary.
Example: In a 400 V unit the smallest capacitor is of 60 kvar with a current transformer having
a ratio of 500/5, and the calculation would be made as follows:
Current of the smallest capacitor Ic:
The C/K value is: 0.866.
If the power of 60 kvar is referenced at 440 V, it should be multiplied by Vgrid
2
/440
2,
in which case the C/K value of the previous example would be 0.72.
If the C/K is congured lower than the actual value, connections and disconnec-
tions would occur continuously with few load variations (the system performs
more operations than necessary).
If the C/K is congured higher, the regulator requires a higher demand for reac-
tive power in order to switch and perform fewer operations.
83
Instruction Manual
Controller MASTER control VAR FAST
To Next Page
Loading...
Need help?
General
