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.