The first time I got into a sub-station had me interacting with a bank of capacitors arranged outside, so many and huge that I had to inquire what role they played.Understandably from my point of view,I had only played with tiny ones that we use in the circuits and PCBs,and all I could get as a response was something to do with **'The Power Factor'(PF)**

fig.1: capacitor bank in a sub-station,(credits:sharda electronics)

In a mathematical perspective,the *PF is the cosine of the angle between True power and Apparent power.*

Another way to look at PF is as the ratio of True Power to Apparent Power.

**True Power**is the energy dissipated by the resistive elements of a circuit and which actually does work like heating/lighting(Watts)

**Reactive Power**is the quantity of “unused” power that is developed by reactive components in an AC circuit or system(VAr)

**Apparent power**is the aggregate of the two(VA)

In short,PF is a quantifying term used to describe the balance of the reactive and true power,necessary for maintaining system stability, voltage levels, and minimizing losses in transmission and distribution systems.

The ratio's maximum value is 1( ideal)while the minimum is 0;values closer to 1 are referred to as good PF while values less than 0.7 are poor PFs and so on.

### The Beer Analogy

In an economic POV,one has to fully pay for a beer which usually contains foam and the liquid itself,even though foam is not valuable to the consumer.

In the same way,one pays a power supplier all costs irregardless of whether they have direct usage or not,meaning PF is much more than just a ratio.

### Significance

From the above definitions,one can say the PF is the efficiency of the system expressed as a decimal or percentage,and like any other system,the higher the efficiency,the more useful and less costly it is.

A poor PF with a value towards zero (0) will consume wasted power reducing the efficiency of the circuit, while a circuit or load with a power factor closer to one (1.0) or unity (100%), will be more efficient. This is because a circuit or load with a low PF requires more current than the same circuit or load with a PF closer to 1.0 (unity).

So when a consumer's load i.e motor, draws more current from the system,it means more infrastructure like better insulation is needed so as to handle more current.

A supplier therefore charges for this low PF or high reactive power.

**CASE STUDY**

Suppose you have 2 motors;one with a PF of 0.9,10kW output and another with PF of 0.7,10kW output.

From the relationship between True and Apparent power;

a)10kW/0.9=11.1kVA

b)10kW/0.7=14.3kVA-this implies more power is required from the supply to achieve the 10kW output,inefficient isn't it?

**Causes of poor PF**

The higher the reactive power,the lower the PF.Reactive power is energy that goes through reactive elements.

**reactive element**is an electrical component or device that stores and releases energy periodically, leading to a phase difference between voltage and current in an alternating current (AC) circuit.They include capacitors and inductors.

Since these elements store energy,and depending on whether current leads or lags voltage,we get a leading or lagging PF.

### Correcting poor PF

From the perks about having PFs approaching 0,there surely has to be a way to combat this.

Most loads like motors are inductive,therefore we have lagging PF,implying that current lags voltage by a certain phase angle.

To mitigate this,capacitors which have current waveforms leading are introduced to reduce the difference.Practically,they are connected in parallel with the inductive loads.

The same applies to capacitive loads which have leading PF,therefore require inductors to reduce the reactive effect.

**CONCLUSION**

A lot can be said about Power Factor,but one of the most exciting thing is how technology plays a huge role in identifying and correcting low PF through relays,sensors and decentralization systems in general.This is a huge topic and I would like to take it head-on as a sequel to this introduction.

*The author is an EE student with interests in tech and writing.*