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Capacitor Inrush Current Calculations

(This is a continuation of the basic formulas. This shows the derivation of the inrush calculations from IEEEC37.99.)

From IEEE C37.99-1980

Energizing An Isolated Bank:

IMAX =

(20)

CB is the bank capacitance in microfarads
LS is the system inductance in microhenries.

As stated KVAR =from (16)

CB =

(21)

Then Substitute CB from (20) with formula (21) we get

IMAX =

= Peak to Peak Voltage

(22)

is approximately 31,622.8
IMAX =  

(23)

19.4163 @ 60Hz, or
(17.7245 @ 50Hz)

Then

IMAX =

(24)

LET V =

This will allow us to re-arrange (24) to the following

IMAX =

(25)

(26)

Giving us the following inrush formulas

For 60 Hz

(27)
For 50 Hz

(28)

 

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