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 Post subject: Determining Capacitance of 3-Phase Capacitor Banks
PostPosted: Tue Aug 18, 2020 4:25 pm 

Joined: Tue Aug 18, 2020 3:14 pm
Posts: 3
Hello,

I have a very basic question on how to determine the capacitance for a 3-Ph capacitor bank.

If I am not mistaken this is done using the following equation:
Capacitor Reactance = kV^2/Mvar
Terefore Capcitance= 1/ (Xc*2*pi*60)

Where:
Mvar is the power is in Mvar
Vrms is the rms voltage Line to Line Voltage in kV
Freq is the frequency in Hz
Capacitance is in farads

Now if the equations above using the following sample nameplate data:
10 kVar @ 480 Volts for a 3Ph bank.
Attachment:
Eaton1.jpg


Xc= (0.480)^2 / (10kVar/1000) = 23.04 ohms
Therefore Capcitance= 1/ (Xc*2*pi*60) =0.000115129 Farads or 115.129 uF

Are the results above the per phase or the total 3-Ph reactance and capacitance of the bank?


Also how would the calculation above change for a bank made up of multiple capacitors?
For example in the case below where 8 capacitors make up the capaitor bank.
Attachment:
Multi_Eaton2.jpg


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 Post subject: Re: Determining Capacitance of 3-Phase Capacitor Banks
PostPosted: Mon Aug 24, 2020 7:50 am 

Joined: Mon May 18, 2020 8:42 am
Posts: 2
Instead of giving you a direct answer, can I suggest you do a similar calculation for a three-phase 100kW 480V resistor. Is your answer for a single-phase or the total resistance?


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