Sungrow SG500MX Operation Manual page 47

Operation Manual
"Islanding" is a potential threaten to devices and operators.

If the inverter continues power supply after the grid is out of power supply, death or injury
may occur to the maintainers during maintenance.

When power grid fails, the inverter continues power supply. Once the grid resumes, a surge
current may occur and damage devices.
Inverter is equipped with anti-islanding protection function.
In anti-islanding protection state, high voltage is still present. Disconnect the main
switch and discharge before testing or maintenance.
Reverse polarity protection
When the PV array inputs' polarities are connected reversely, inverter will stop and protect itself
against damage and resume normal operation after the connection is corrected.
Overload protection
When the PV array output power exceeds the inverter permissible maximum input power,
inverter will limit the power yield at maximum AC power point. If the temperature exceeds the
permissible value, inverter will automatically stop operating unless the condition resumes
normal.
Ground protection
The grounding cables are equipped with the leakage current sensor. When the leakage current is
detected to exceed the setting value (default value is 5A, can be set from the LCD screen) ,
system will send instruction to stop the inverter and display the fault type on the LCD screen.
Module over-temperature protection
IGBT modules inside the inverter uses thermal sensor with high-precision to monitor the
real-time module temperature. Once the module temperature is detected to be high, DSP will
send direction to stop the inverter or derate the output.
Internal over-temperature protection
The inverter is equipped with high-precision thermal sensor to monitor the internal temperature
of the inverter. Once the over-temperature is detected, DSP will help to maintain the safe
operation of the inverter by sending instruction to stop the inverter or derate the power output.
8 Inverter Functions
41