### POWER CAPACITORS

**Energy Saved is Energy Produced!**

The demand for power has increased exponentially, resulting in growing awareness of power quality. Enhancing power quality by improving power factor and harmonic filtering results in energy savings and a fast return on investment.

In Direct Current (DC) Circuits, only resistance restricts the current flow. In Alternating Current (AC) Circuits, there are additional aspects which determines the current flow. Though similar to resistance, they do not actually consume any power, but load the system with reactive currents, and are hence called “Reactance”.

Reactance is either caused by inductance, when current lags the voltage, or by capacitance when current leads the voltage. All industrial and commercial loads are inductive in nature, leading to unnecessary loading of the system, while performing no real work. To counter this lagging current, leading current should be added in the circuit. This leading current is added by introducing capacitors in the circuit.

The above phenomenon can also be described by the following Power Triangle:

**Real Powe**r: Also known as active power, is the energy used to do actual useful work and is measured in watts (W).

**Apparent Power**: Is the total current drawn from the generator and is measured in volt amperes (VA).

**Reactive Power**: This occurs in an AC circuit when voltage and current are not in phase and is measured in volt ampere reactive (var).

The reactive power can be ”supplied” by a capacitor, thereby reducing the phase angle.

Power Factor is the ratio of real power (W) / Apparent Power (VA). When W=VA, then the power factor is 1 or unity.

**Advantages of power factor correction:**

- Avoid the penalty applied by the energy suppliers to the users with low PF.
- For new plants, optimize the dimensioning of the plant depending on the actual planned production.
- For existing plants, recover productive capability without adding/increasing the performances of what is already installed (transformers, cables).
- Reduce line voltage drop.
- Reduce energy losses due to Joule effect in transformers and cables.