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A8. Individual phase power factor control (applicable for Three Phase
Model RVT12-3P)
By default only the '12 outputs' model is available for individual power factor control.
As in the base RVT, the PFC control in the three-phase RVT 12-3P is done by comparing
the C/k value to the fundamental reactive current measurement.
The control is done in different ways, based on the connection type (see
connection type illustration and CT wiring on the controller
the output steps (single or three phase steps).
Taking the connection type notation (please refer to
and CT wiring on the controller
wPh- xLyz
w determines a single or three phase network
x is the number of voltage measurements used
y determines Line to Line or Line to Neutral connection
z is the number of CT used
wPh-1Ly1 control type (only one CT)
Basically, if only one CT is used, the control is done according the CT in phase L1 (or the
line where the CT is placed).
3Ph-xLy2 and 3Ph-xLy3 control type (2 or 3 CT)
If more than one CT is used, the control strategy follows a simple and efficient principle
to be able to handle all the outputs in a comprehensive way. The following strategy is
implemented:
Unbalanced network switching strategy:
Wait for the switching delay time while calculating the reactive current in phases L1, L2,
and L3 according the Normal/Integral setting
Evaluation of the minimum 3 phase outputs to be switched ON or OFF
Evaluation of the single phase outputs to be switched ON or OFF
If any block of single phase outputs (already ON and to be switched ON) can be
transferred to a three phase step then switch preferably a three phase output
Switch ON or OFF according the Progressive/Direct, Linear/Circular settings
Some typical examples are given hereafter:
-
12 single phase capacitors / 1 CT (1Ph-1LL1 only)
àThe control is done through the CT in the phase where it is placed
àC/k 3Ph parameter is used for steps switching (equivalent to C/k parameter in
base RVT6 or 12)
76 Appendices ç Manual Power Factor Controller RVT
terminals)
where :
terminals) and the type of
A7. CT connection type illustration
A7. CT
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