Other Faults - Sungrow SG500MX Operation Manual

10 Troubleshooting
Fault LVRT Run
Grid voltage is below 0.9Un and the LVRT function is enabled
Possible
reason
Warn will disappear automatically when grid voltage recover normal
Measure
Remark -
CT-Unbalanced
Fault
Possible Current transformer (CT) on the inverter control cabinet is abnormal
reason
Measure Check and service the CT on the measuring board when inverter is voltage-free
-
Remark
Fault RISO-low
Inverter DC side insulation resistance is lower than the set value.
Possible
reason
Measure -
Remark Only alarm display. Inverter can operate normally.
DC Sensor-err
Fault
Possible Inverter DC sensor abnormal
reason
Check and service the DC sensor when inverter is voltage-free
Measure
-
Remark
10.5

Other Faults

Inverter Shuts Down Shortly After Start-Up
Possible reason: DC input voltage just reaches the inverter start-up voltage. Voltage will decrease
and inverter will stop when it is under load.
Solution: design the serial and parallel connection in accordance with the open circuit voltage;
increase the input DC voltage; avoid adopting the critical voltage.
Hear-Sink is Over-Temperature
Possible reason: cooling fan failure; over-temperature of the air inlet; bad ventilation of the
switch room, etc..
Solution: check and replace the cooling fan; reduce the temperature of the switch room; clean
the air duct and widen the air duct.
Noise is Too Loud during Inverter Operation
Possible reason: abnormal operation of the inverter and transformer; fan failure.
Solution: check if the power is within the permissible range; measure if the grid-connected
current and voltage waveform are normal (if not, the noise will be loud and the transformer will
be overheating); check and replace the fan.
LCD Display Cannot Start or Stop Inverter
Possible reason: communication malfunction between the LCD display and the DSP; LCD power
supply malfunction.
Solution: check the connection between the LCD display and the DSP.
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Operation Manual