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Ipk*f limits for circuit breakers.

Ipk*f limits for circuit breakers.

Ipk*f limits for circuit breakers.

(OP)

CODE

I am trying to check if the general purpose circuit breakers at a substation can withstand the outrush of a capacitor bank.  From ANSI c37.06-2000, "The Product of the transient inrush current peak and transient inrush current frequency shall not exceed 2 x 10^7."  Does this mean:
2 x 10^7 >= 2* pi * ipk * f                        (1)

Or:
2 x 10^7 >= ipk * f                                (2)


IEEE 1036 says that the limit is

ipk*f =V0/(2*pi*L)                                 (3)

which is equivalent to eq. 2.  However, the rating is refered to as a maximum rate of rise limitation.  Assuming a sinusoidal current, this would simply be the maximum of the derivitive of the current:

I = Ipksin(2 * pi * f * t)                         (4)

di/dt = Ipk * 2 * pi * f * sin( 2 * pi *f *t)      (5)

maxdi/dt = Ipk * 2 * pi * f                        (6)

Thus giving equation 1.  

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