We have installed a large number of static capacitors for our system power
factor improvement. But the utility which supplies us the power is not in a
position to provide us a constant frequency of 50 Hz. At times it goes below
48 hz. This continues for long hours during peak period.
All the capacitors are 50 KVAR, 440 V, 50 hz. All PP capacitors. Since the
KVAR is directly dependant on the Square of the Voltage applied and the
frequency, will the low frequency reduce the KVAR correction ? If so then
the over all power factor of the system may go down or not ?

Regards,
S.R.K

Yes, as the supply frequency reduces, the capacitor current will reduce and the inductive current will increase. This will aftec the power factor causing it to reduce, however it is probably not a major problem as the reduction would be relatively small.
:)