Reset In Inverse-Time Modes - ABB RELION REX640 Technical Manual

1MRS759142 C
11.2.2
REX640
Technical Manual

Reset in inverse-time modes

The user can select the reset characteristics by using the Type of reset curve setting.
Table 1474: Values for reset mode
Setting name
Type of reset curve
Immediate reset
If the Type of reset curve setting in a drop-off case is selected as "Immediate", the
inverse timer resets immediately.
Definite time reset
The definite type of reset in the inverse-time mode can be achieved by setting the Type
of reset curve parameter to "Def time reset". As a result, the operate inverse-time
counter is frozen for the time determined with the Reset delay time setting after the
current drops below the set Start value, including hysteresis.The integral sum of the
inverse-time counter is reset, if another start does not occur during the reset delay.
If the Type of reset curve setting is selected as "Def time reset", the
current level has no influence on the reset characteristic.
Inverse reset
Inverse reset curves are available only for ANSI and user-
programmable curves. If you use other curve types, immediate reset
occurs.
Standard delayed inverse reset
The reset characteristic required in ANSI (IEEE) inverse-time modes is provided by
setting the Type of reset curve parameter to "Inverse reset". In this mode, the time
delay for reset is given with the following formula using the coefficient D, which has
its values defined in the table below.
 
 
D
t s [ ] = k
 
⋅
2
 I 
 
1
 −
 

I
>
 
 
GUID-D324E98B-F672-4029-8322-054AE0E29CD3 V1 EN
General function block features
Possible values
1=Immediate
2=Def time reset
3=Inverse reset
Section 11
(Equation 359)
1681