A power factor correction unit is equipment used to improve power
factor, in industrial networks. It usually consists of a number of
capacitors that are switched by means of a contactor. These contactors
are controlled by a regulator (digital varmetric relay), that measures
power factor in an electrical network. To be able to measure 'power
factor', the regulator uses a CT (current transformer) that measures
the current in the 1st phase (3-phase network), usually a CT is chosen
with a primary current adapted to the network current, and a secondary
current of 5 amps (depends on the regulator).
Depending on the
load and power factor of the network, the regulator will switch the
necessary steps to make sure the power factor stays above 0.9 (which
is usually demanded by the energy supplier).
