ABB distribution protection unit 2000R defines inverse-time characteristics not according IEEE Std C37.112-1996. Still they call their curve for example "IEEE Very Inverse". The eqation is the same, but the parameters don't match.
Parameters: IEEE Std C37.112-1996: A=19.61, B=0.491, p=2
ABB 2000R: 2.855, B=0.0712, p=2
"Extremely inverse" parameters don't match either.
What is this ABB version of IEEE inverse-time?
O.B.