ABB REB670 Series Applications Manual page 173

1MRK 505 370-UEN D
Normally it is required that the negative sequence overcurrent function shall reset as fast as
possible when the current level gets lower than the operation level. In some cases some sort of
delayed reset is required. Therefore different kinds of reset characteristics can be used.
For some protection applications there can be a need to change the current operating level for
some time. Therefore there is a possibility to give a setting of a multiplication factor
the negative sequence current pick-up level. This multiplication factor is activated from a
binary input signal ENMULTx to the function.
7.4.3 Setting guidelines
The parameters for Four step negative sequence overcurrent protection NS4PTOC are set via
the local HMI or Protection and Control Manager (PCM600).
The following settings can be done for the four step negative sequence overcurrent
protection:
Operation : Sets the protection to On or Off .
Common base IED values for the primary current (
power (
GlobalBaseSel : Selects the global base value group used by the function to define IBase , UBase
SBase . Note that this function will only use IBase value.
and
7.4.3.1 Settings for each step
DirModeSelx : The directional mode of step x. Possible settings are off/nondirectional/
forward/reverse.
Characteristx : Selection of time characteristic for step x . Definite time delay and different
types of inverse time characteristics are available.
Table 31:
Curve name
ANSI Extremely Inverse
ANSI Very Inverse
ANSI Normal Inverse
ANSI Moderately Inverse
ANSI/IEEE Definite time
ANSI Long Time Extremely Inverse
ANSI Long Time Very Inverse
ANSI Long Time Inverse
Table continues on next page
Busbar protection REB670
Application manual
SBase ) are set in global base values for settings function GBASVAL.
When inverse time overcurrent characteristic is selected, the operate time of
the stage will be the sum of the inverse time delay and the set definite time
delay. Thus, if only the inverse time delay is required, it is important to set the
definite time delay for that stage to zero.
x means step 1, 2, 3 and 4.
Inverse time characteristics
GUID-460D6C58-598C-421E-AA9E-FD240210A6CC v3
IBase ), primary voltage ( UBase ) and primary
GUID-CFB327EF-C5C4-44B5-AB4B-9C2916355FC5 v5
Section 7
Current protection
IxMult to
GUID-F7AA2194-4D1C-4475-8853-C7D064912614 v4
167