ABB RED615 Technical Manual page 521

1YHT530004D05 D
615 series
Technical Manual
I_A
I_B detector
I_C
Io detector
OPR_MODE
REM_FLT_ARC
FLT_ARC
BLOCK
A070746 V4 EN
Figure 268: Functional module diagram. I_A, I_B and I_C represent phase
currents.
Level detector 1
The measured phase currents are compared phasewise to the set Phase start value.
If the measured value exceeds the set Phase start value, the level detector reports
the exceeding of the value to the operation mode selector.
Level detector 2
The measured residual currents are compared to the set Ground start value. If the
measured value exceeds the set Ground start value, the level detector reports the
exceeding of the value to the operation mode selector.
Operation mode selector
Depending on the Operation mode setting, the operation mode selector makes sure
that all required criteria are fulfilled for a reliable decision of an arc fault situation.
The user can select either "Light+current", "Light only" or "BI controlled"
operation mode. The operation is based on both current and light information in "Light
+current" mode, on light information only in "Light only" mode or on remotely
controlled information in "BI controlled" mode. When the "BI controlled" mode is
in use and the OPR_MODE input is activated, the operation of the function is based
on light information only. When the OPR_MODE input is deactivated, the operation
of the function is based on both light and current information. When the required
criteria are met, the drop-off timer is activated.
Drop-off timer
Once activated, the drop-off timer remains active until the input is deactivated or at
least during the drop-off time. The BLOCK signal can be used to block the
OPERATE signal or the light signal output ARC_FLT_DET.
Level
1
Operation
mode
selector
Level
2
Section 4
Protection functions
Dropoff
OPERATE
t
Dropoff
ARC_FLT_DET
t
515