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.
ARC light detection
ARC detection information is received directly from the relay hardware input. The
detected ARC fault is directly signalled to the Operation mode selector and Fixed
delay 2 modules. There are four ARC detection inputs in the protection relay. Each
input is connected to a dedicated ARCSARC function.
Table 1028: ARC detection inputs connected to ARCSARC
ARC input
ARC protection function
X11/ARC
ARCSARC1
X12/ARC
ARCSARC2
X13/ARC
ARCSARC3
X14/ARC
ARCSARC4
Operation mode selector
Depending on the
Operation mode setting, Operation mode selector makes sure
that all required criteria are fulfilled for a reliable decision of an arc fault situation.
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, Fixed delay 1 timer is activated.
Fixed delay 1
Once this timer is activated, the
OPERATE
signal output is activated immediately.
The output is kept active for minimum 25 ms or as long as the input is activated.
The
BLOCK
signal can be used to block the
OPERATE
signal.
Fixed delay 2
Once this timer is activated, the
ARC_FLT_DET
output is activated immediately. The
output is kept active for minimum 25 ms or as long as the input is activated. The
BLOCK
signal can be used to block the ARC light signal output
ARC_FLT_DET
.
Supervision
If a faulty arc sensor is internally detected or if the connection to the arc sensor is
lost,
ALARM
output is activated if
Sensor supervision is set to "on".
When
Sensor supervision is set to "off",
ALARM
output stays false even though the
arc sensor is faulty or unconnected.
1MRS759142 F
Protection functions
REX640
Technical Manual
1087