When to use a capacitor bank ?

Thread Starter

YoGMan

Joined Sep 20, 2017
76
Hello guys, the power factor at my University drops to 0.8 during holidays. I am given to redesign the electrical system. Is a capacitor bank needed here to improve the power factor ?
 

crutschow

Joined Mar 14, 2008
25,646
Hello guys, the power factor at my University drops to 0.8 during holidays. I am given to redesign the electrical system. Is a capacitor bank needed here to improve the power factor ?
To know for sure, you need to know whether the power factor is leading or lagging.
Typically it's lagging due to typical motor and other inductive type loads so for that, you would use a capacitor bank.
But note that the bank may need to be very large, depending upon the value of the reactive current required to significantly improve the power factor.
 
Last edited:

ebp

Joined Feb 8, 2018
2,332
The assumption is often that the issue is simply difference in phase between current and voltage. This is true if the contributors to low power factor are linear loads. It is not true with non-linear loads. Many electronic devices present a very non-linear load. The peak of the current coincides with the peak of the voltage (slight but mostly insignificant phase difference), but the current waveform is not sinusoidal - no current flows for much of each half cycle. This is something that cannot be compensated for by adding linear reactance external to the devices. The current waveforms must be evaluated. I think it is likely that the poor power factor is due to a mixture of non-linear loads and inductive loads. High-power linear capacitive loads are not common.
 
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