Why capacitor is connected in parallel not in series for Power Factor improvement?

What is Power Factor improvement?

In simple language, power factor improvement is the process of keeping the power factor unity or almost near unity.

Always remember that if power factor is unity or nearly unity then it is good. When a load is connected with an AC supply then it draws current from the source. If the load is inductive then the current drawn by the load will be lag behind the voltage but if the load is capacitive then the current drawn by the load will be lead behind the voltage.

So both lagging or leading current can creates power loss. So we need to keep the power factor near unity.

How we can improvement Power Factor?

Suppose an inductive load is connected to a source. So it draws the lagging current. In this case, we can compensate the lagging current by flowing leading current. So we have to connect any device or load which can draw leading current such as the capacitor, synchronous motor.

If a capacitive load is connected to a source then it draws leading current. In this case, we can compensate the leading current by flowing lagging current. So we have to connect any device or which can draw lagging current such as an inductor.

Why we connect Capacitor in parallel, not in series?

Reason 1

We know that in series connection Current is constant and voltage is varying but in parallel connection, voltage is constant and current is varying. 

So we need to keep constant the voltage across the load. So if we connect a capacitor in parallel it will be drawn leading current according to its rated value. But if we connect a capacitor in parallel then the flow of current through the capacitor will depend on the load.

Reason 2

As in the case of series connection of capacitor current fully depends upon the load so we need a capacitor of high value which can deliver the full load current.

Reason 3

If we connect a capacitor in series with the load for power factor improvement then a voltage will be dropped by the capacitor.

Reason 4

If we connect the capacitor in series with the load then if short circuit fault occurs in the load then the total voltage will be applied to the capacitor which may blow them.

Reason 5

In case of series connection, if we want to connect additional capacitor then we need to open the whole circuit. But in case of parallel connection, we can easily connect an additional capacitor in parallel with the existing capacitor.

Reason 6

If we connect the capacitor in series with the load for power factor improvement then the recovery voltage across the contacts of the switchgear shall be high.

Read Also:

• Why Capacitor is used in Single phase Induction Motor?
• Why Alternator Armature Winding always connected in STAR?
• Why Current, Voltage changes But Power, Frequency constant in Transformer?
• Can DC Motor run on AC supply and Vice-Versa?

Thank you for visiting the website. keep visiting for more updates.