ABB REB670 - Page 215

Curve name
Instantaneous
IEC Reset (constant time)
ANSI Reset (inverse time)
The different reset characteristics are described in the Technical Reference Manual
(TRM). There are some restrictions regarding the choice of reset delay.
For the independent time delay characteristics the possible delay time settings are
instantaneous (1) and IEC (2 = set constant time reset).
For ANSI inverse time delay characteristics all three types of reset time characteristics
are available; instantaneous (1), IEC (2 = set constant time reset) and ANSI (3 =
current dependent reset time).
For IEC inverse time delay characteristics the possible delay time settings are
instantaneous (1) and IEC (2 = set constant time reset).
For the programmable inverse time delay characteristics all three types of reset time
characteristics are available; instantaneous (1), IEC (2 = set constant time reset) and
ANSI (3 = current dependent reset time). If the current dependent type is used settings
pr
, tr and cr must be given.
tPCrvx, tACrvx, tBCrvx, tCCrvx: Parameters for programmable inverse time
characteristic curve. The time characteristic equation is according to equation
37:
[ ]
p
A
t s B TD
i
C
ipickup
= + ×
-
æ ö
ç ÷
ç ÷
ç ÷
æ ö
ç ÷
ç ÷
è ø
è ø
EQUATION1722 V1 EN-US (Equation 37)
Further description can be found in the Technical reference manual (TRM).
tPRCrvx, tTRCrvx, tCRCrvx: Parameters for customer creation of inverse reset time
characteristic curve. Further description can be found in the Technical Reference
Manual.
1MRK 505 370-UUS A Section 7
Current protection
Busbar protection REB670 2.2 ANSI 209
Application manual