Arc Detection/Interruption; Warning Notices Affixed To The Device - Fronius Symo Serie Instructions De Service

Insulation monitor (IMI/RCMU)
The IMI (isolation monitor interruptor) feature is performed by the RCMU (residual current
monitoring unit) feature in the inverter. This feature automatically monitors whether a leak-
age current exists in the grid power feed operation. The inverter is disconnected from the
grid if a defined leakage current is exceeded.
Insulation monitoring of ungrounded solar modules
In the case of grid connected photovoltaic systems with ungrounded solar modules, the in-
verter checks the insulation resistance between the positive and negative pole in relation
to the earth potential before energy is fed into the grid. The inverter issues a state code if
the insulation resistance is too low. The inverter is therefore not permitted to start feeding
energy into the grid.
Arc detection/in- The inverter is equipped with integrated arc detection/interruption, which detects and ex-
terruption tinguishes serial arcs.
For example, a serial arc can occur after the following errors or situations:
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If a serial arc is detected, the power is switched off and the grid power feed operation is
interrupted. A state code is shown on the display. The state code on the display must be
manually reset before the grid power feed operation can be resumed.
The power shutdown also extinguishes the serial arc.
Warning Notices There are warning notices and safety symbols on and in the inverter. These warning notic-
Affixed to the De- es and safety symbols must not be removed or painted over. They warn against incorrect
vice operation, as this may result in serious injury and damage.
NOTE! Automatic reconnection no longer occurs after the device is disconnected
from the grid five times as a result of exceeding the defined leakage current value.
The State Code 607 shown on the display must be acknowledged to reconnect.
Poorly-connected plug connections on the solar module
Poor or defective cable connections on the solar module side, which enable a connec-
tion against the earth potential
Defective solar modules due to problems in the junction box or production errors, such
as high resistance solder connections in individual solar cells
Cables incorrectly connected to an inverter's input terminals
NOTE! This product is equipped with a communication interface in line with the
"Communication Signal for Rapid Shutdown - SunSpec Interoperability Specifica-
tion". Power optimizers and other MLPE features in the photovoltaic system can
impair the correct functioning of the arc detection/interruption. When using these
kinds of components, the system installer is responsible for ensuring the correct
functioning of the arc detection/interruption. Contact your Fronius Technical Sup-
port for more information.
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