25
CBEMA curve based on voltage standard
Method to classify
voltage sags as “acceptable” or “unacceptable”
using CBEMA
V(t)=Vend+0.288e-1.06t+(0.712-Vend)e-23.7t
V(t) = DC circuit voltage for a rectifier. This is the voltage
which is checked versus the voltage standard
VTH (the threshold voltage in p.u below which
a voltage sag is classified “unacceptable”)
Vend = final DC Voltage if fault persists
Sag is considered “unacceptable” if V(t)
< 0.87