Capacitor banks
What is this capacitor bank? How can it reduce the electricity bill?Can a capacitor bank be installed in a factory?Is it only the reduction of the electricity bill by installing the capacitor bank?
Today we will look at these facts.
First of all, before knowing the capacitor bank or Power Factor Correction System (this is the right name), you should know the following basic facts.
(Capacitor bank is abbreviated as Cap bank from here)
Before talking about cap bank, the main thing to know is about power factor.
What is this power factor (PF)?
Simply put, the ratio between the amount of electricity we get and the electricity we use. That means that 100% of the electricity we get will not be used.
What will happen to the rest?
That’s when the words kVA, kW, kVAr (Apparent power, Active power, Reactive power) come.The best and most famous example to explain these three words is the example of a beer glass (break the can and pour it in your mouth, this is a bit unfamiliar to us, children who have not drunk beer, imagine that the glass is Coca Cola –
Now that foam is not a bit of useless waste, Reactive power (kvar) is for such useless waste, and Active power (kw) is for the beer you drink. That said, the few that we actually used.
Then the apparent power is the kw and kvar inside the whole glass of beer we bought.# kVA=kW + kvar
Now people are getting a lot of questions, what is this useless Reactive power, how is it created, the money is being paid for this, and how to get rid of it.
After investigating for a while, it is understood that this reactive power is what heats up and makes noise in some electrical devices, like motors.
That means, in the case of a motor, when electrical energy is converted into kinetic energy, reactive power is the power generated by it.
The heating of that cable also belongs to reactive power.So, as a solution to this, there are solutions like applying pure copper to the winding of the motor, making the winding very precise, and reducing the length of the cable as much as possible. But these solutions lose a significant advantage.That’s why scientists are researching more about this.
I mean this time before eighteen hundred years. So, to find a successful solution, scientists have to seek the help of mathematics.According to the behavior of these three reactive, active and apparent power, a relationship is built with geometrical mathematics. That is how the famous power triangle is born.
(He makes this from things like Pythagoras theorem, vectors, trigonometry)
Now the cos value of the angle called pi, which means the hypotenuse/hypogon, is equal to the power factor I mentioned earlier.# Cos ɸ= Power factorNow, if you look a little more closely, you can see that the reactive power decreases, which means that the angle called pi also decreases
.It means that the more the value of the power factor or pi angle becomes zero, that is, the more the value of cos becomes one or close to one, the more the reactive power decreases. According to the Pythagorean theorem, the value of the contact point decreases, the kva in the corner or here decreases, which means the electricity bill decreases.
But what do you use to reduce the pie?? Hand drawn??So scientists have been thinking for a long time about something that can reduce the pi angle. While thinking about it, I saw something very strange. When some machines are working in factories, this pi angle decreases or the power factor reaches a value close to one.Before the work started, scientists divided everything that uses electricity into three main parts, and observed the behavior of the voltage and current of those three parts. Accordingly, all electrical loads are divided into three main parts.Resistive load (electrical heater, lights…)Inductive load (motors, transformers…)Capacitive load
The relative behavior of the voltage and current of those three types of loads is graphed as follows The x-axis of the graph represents time and the y-axis represents change
When you look at the graphs of the resistive load, you can see that there is very little difference between the voltage and the current. That is to say, the load draws the current at the same speed as the voltage. When the heater is loaded on, the analyzer shows that the power factor improves, but at the same time, the Ampere shows a much higher value. What happens there is that heaters work more efficiently compared to other equipment in the factory and consume more current.When you look at the inductive load graph, you can see that the current comes much later than the voltage (current lagging).
It’s like if you just put a lot of sand and half of the poison mask. . Most of the loads in many factories belong to this type.When taking the capacitive load graph, it can be seen that the current is ahead of the voltage. (current leading).
This is a dial that works more than what it pays for. Capacitor stores electrons or current and releases it. When it is released, it acts like a battery.
At that time, it does not take voltage from the system. .Now the concept of capacitor bank is born.If the power factor of any factory shows a very low value, 0.98, then capacitor bank can be installed there.One may ask whether it is possible to reduce the kva further by adding a cap bank to a place where the power factor has improved from electrical heaters, but simply put, it is not.The current is led by the capacitor.
If the capacitor is added to a place where the power factor is 0.99, the power factor becomes leading. Remember the power triangle, when the reactive power is the least, when the pi angle is 0, the apparent power and active power are equal. Beyond that, if the pi angle increases to the other side, then the reactive power increases again. Then the current that discharges the capacitor is added as a reactive power. So remember to have the power factor at the time of lagging.
Now let’s see how to install a capacitor bank in a factory:-
When you notify a company that installs a cap bank, the first thing they do is take a power reading. It is done by connecting a power quality analyzer to the place where the full load is caught in the factory.It is necessary to fully load the factory during the reading of this analyzer. Also, the factory must be run at the same load that it runs on a daily basis.
The power quality analyzer sometimes takes an hour to take a reading, sometimes it takes two or three days. The running time of the analyzer varies according to the load pattern of the factory.
The other important thing is that if you hope to install new machines in the future, you should also inform the relevant institution about that.Therefore, factories often ask for upgradable cap bank that is 15% more than the current requirement.
#capacitor bank
