Siemens SICHARGE UC 150 Operating Instructions Manual page 25

Description
3.6 Electrical protection devices
3.6 Electrical protection devices
The charging station is equipped with several electrical protection devices.
Overvoltage protection
The charging station has comprehensive protection against overvoltages from the
distribution network. Surge arresters with short response times protect each line conductor of
the power cable against overvoltages. In addition, the control system of the charging station
constantly monitors the mains voltage. If the mains voltage exceeds or falls below the
permissible limits, the charging station interrupts a charging process in progress or does not
start the charging process.
Overload protection
The charging station constantly monitors the input current and the output current. If a
measured current exceeds the limit values during a charging process, the charging station
stops the charging process. The output contactors are opened so that no current flows to the
vehicle. For increased safety, the input contactors are opened and the converter is thus
disconnected from the input.
The charging station and the vehicle are also protected by a circuit breaker that opens in the
event of an overcurrent at the input, as well as two output fuses (one per output) that open
in the event of an overcurrent at the output.
Insulation monitoring
To ensure that an electric vehicle is safe, the vehicle's high-voltage electrical system must not
be grounded via electrically conductive material. For this reason, an insulation monitoring
device in the charging station constantly monitors the resistance between the DC+ and DC-
contacts to earth. If this resistance falls below the permissible limit value, the insulation
monitoring device switches off the output current. In addition, the insulation monitoring
device sends a message to the Siemens control system. For safety reasons, the charging
station switches to the safe DC shutdown state. The charging station can no longer be
operated in the DC shutdown state. To reset the charging station, the user must confirm the
alarm. When the alarm disappears, the charging station is ready for use again. If the alarm
remains active, there is still an error and the station is not ready for operation. You will find
further information in "Handling alarms and errors (Page 74)".
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Operating Instructions, 10/2022, A5E50068475-AB
SICHARGE UC 150