by Nurin Ilyana.
Power Factor is used to measure the efficiency of energy. The measurement value ranges from 0 to 1, with the ideal value being 1. The smaller the number, the less efficient the machine while a higher number would indicate a more efficient machine. You can calculate power factor using the formula below;
Let’s look at Power Factor, as something most of us Malaysians can relate to, Teh Tarik. As you know Teh Tarik consists of its frothy foam and the delicious tea itself, and a glass to contain it. How does it relate to power factor you say? Well let’s take the True Power (kW) to be the Tea making it useful power, the foam to be not useful power, while the Apparent Power (kVA) acts as the whole glass consisting of the tea and foam that you have to pay for. So now the equation might look a little something like this;
For customers taking supply at 33 kV or below, the value of the power factor to be maintained is ≥ 0.85. Power factor < 0.85 will result in power factor surcharge.
For customers taking supply at 132 kV or above, the value of the power factor to be maintained is ≥ 0.90. Power factor < 0.90 will result in power factor surcharge.
So it’s simply the less the foam, the more the tea, and the better value you would have for your money.
How is your equipment inefficient, you might wonder? Well, equipment that can contribute to a low power factor are mostly large inductive loads, such as power transformers, pumps, air compressors, induction furnaces, and big fans just to name a few. They become inefficient when they’re either partially loaded, have a large quantity of transformers, contain harmonic loss in its system or just wrongly sized capacitors inside the equipment.
Why do you get charged? What does your equipment being inefficient have anything to do with you getting a penalty? Well this is due the fact that, inefficient equipment can cause the current flow in the electrical lines that are from your electrical supplier to your premise, to increase, which will then cause voltage drops, causing voltage fluctuations, which then lead to power quality issues.
Again, “so?” you might say. Well the electrical lines that supply current have a certain capacity and limit as to how much current they can take. Your inefficient equipment, as mentioned, will cause the current to increase in the electrical lines, thus disrupting the distribution capacity. If the lines were to be overloaded, the lines will have trouble in keeping up with the demands of the people in the area, which most definitely includes you. From this you can tell that this will not affect just you, but this will also affect your neighbours too!
Therefore, your inefficient equipment does not only burden you with charges, but it also disrupts the electrical lines’ capacity to deliver power as well as make it harder for your electrical supplier to distribute the electricity to you as well as your neighbours. To cope with this your electrical supplier would either have to replace the lines, or add on new lines to improve and take on more current flow. This obviously all cost money.
How can you improve it? To improve it you would have to make the capacitive load balance out with the inductive load. This can be done by installing a capacitor bank.
In conclusion, take note at how much the power factor is affecting not only you but your neighbours and electrical supplier as well, and from there take steps to improve it.