Capacitor Bank , Power factor Improvement , why use Capacitor Bank

Basic Power Factor Theory:

 

Power Factor compares the active power (kilowatts or kW) with apparent
power (KVA) that is demanded from the power source. It is also a comparison of
the active current to the total current, as shown in the triangle below. It is
also equal to the cosine of the angle of displacement between the voltage and
current waveform. The ratio of actual power to apparent power is usually
expressed in percentage and is called power factor.

 

Generally the Transformers are inductive loads and cause very low
power factor during their testing. Inductive equipment needs magnetizing power
to produce the flux necessary for the operation of inductive devices. The unit
of measure of magnetizing or reactive power is the kilovar (kVAR). The active
power (kW) and reactive power (kVAR) together make up apparent power which is
measured in kilovolt-amperes (kVA). By representing these components (kW and
kVAR) of apparent power (kVA) as the sides of a right triangle, we can
determine the apparent power from the right triangle rule. To reduce the kVA
required for any given load, you must shorten the line that represents the
kVAR. This is the function of power factor correction capacitors or
compensating capacitors.

 

Compensating
capacitors are placed in parallel with the inductive loads and can efficiently
supply the reactive current to inductive loads, so those kilovars do not have
to be sent all the way from the power source to the inductive loads. This
relieves both your electrical system and utility network of the cost of
carrying these extra kilovars. They will also help you to regain system capacity,
improve voltage and reduce branch circuit I²R  Power losses

A Capacitor Bank is a group of capacitors of the same rating that are connected in series or parallel with each other to store electrical energy.