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Participant

Join Date: May 2010
Posts: 1

# Utility Maintenance

05/17/2010 7:41 AM

i m working with a company, our power factor is going low for few weeks, how can i check capacitor capacity and how much rating capacitor should i install to improve power factor

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Commentator

Join Date: Sep 2007
Posts: 98
#1

### Re: utility maintenance

05/17/2010 8:21 AM
 TYPICAL CALULATIONS ARE GIVEN FOR IMPROVING P.F Q1 TO Q2 FOR 567 KW CAPACITOR SIZING CALCULATION FOR CAPACITOR BANK Here, KW = 567.00 KW Q1 = 0.85 Q2 = 0.91 C = KW X (TAN (COS - Q1) - TAN (COS-Q2) ) = 567 X TAN (COS - 0.85) - TAN ( COS-0.91) ) = 567 X (0.62 - 0.455) = 567 X 0.165 = 93.555 KVAR
Guru

Join Date: Feb 2009
Location: Houston, USA
Posts: 947
#2

### Re: utility maintenance

05/17/2010 6:54 PM

- MS

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Power-User

Join Date: May 2010
Posts: 144
#3

### Re: Utility Maintenance

05/18/2010 11:11 AM

From your question, I understand that the problem is started for few weeks only. There were no problem before. So that means your existing design for the selection of capacitor bank is correct. Now, how did you find out that power factor is going less. From the Pf meter?...The solution for your problem is not to add capacitors. But you have to find out the reason for this and rectify it. Investigate the type of load and what are those load when you noticed low power factor. Inspect individually these equipments for example motors, UPS, flouresent lamps etc. If really the initial selection of your capacitor bank is correct, you can find the reason of problem from these equipments. Rectify it.....otherwise ill you add capacitors again, if tomorrow the power factor gone less again??, ( or you just posted for getting information of capacitance selection??

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