Improving The power factor of an electrical installation consist of giving it the means to produce a varying proportion of the reactive energy that it consumes itself.

Different systems are available to produce reactive energy, particularly phase advancers and shunt capacitors (or serial capacitors for major transport networks).

The capacitor is most frequently used given:

• It’s non‐consumption of active energy,

• It’s purchasing cost,

• It’s easy use,

• It’s service life (approximately 10 year),

• It’s very low maintenance (static device)

The capacitor is a receiver composed of two conducting part (electrodes) separated by an insulator. When this receiver is subjected to a sinusoidal voltage, it shifts its current, and therefore it’s (capacitive reactive) power, by 90° forward the voltage.

Conversely, all other receivers (motor, transformer, etc.) shift heir reactive component (inductive reactive power or current) 90° backward the voltage.

The composition of these (inductive or capacitive) reactive powers or current gives a resulting reactive power or current below the existing value before the installation of Capacitors.
In simpler terms, it can be said that inductive receivers (motors, transformers, etc.) cons energy, while capacitors (capacitive receivers) produce reactive energy.