1. The SUN2000 does not generate power and cannot be connected to the grid. The SUN2000 generates an alarm indicating that the grid voltage is abnormal (301-4). The voltage of one phase is only 101 V. Ask the customer to check the actual voltage.
After onsite check, it is found that multiple inverters that report alarms are under the same combiner box. Check the input and output voltages of the combiner box. A copper bar at the main switch of the combiner box is burnt. It is suspected that the internal screws are not tightened, if the switch is damaged due to long-time running, replace the switch and copper bar.
2. Multiple inverters are faulty and cannot run.
According to the log analysis, the SUN2000 runs properly on the day and shuts down properly at night. The SUN2000 fails to run after it is started on the next day, and no abnormal alarm information is reported. The logs of several SUN2000s show the same symptom,
Check the logs carefully. The SUN2000 shuts down for a period of time at night and triggers another data record, as shown in the following figure.
At this time, the DC auxiliary power supply of the inverter starts again. There is no DC voltage at night. Therefore, the auxiliary power supply starts due to lightning strikes. In addition, the current day is also a thunderstorm. Therefore, the problem is caused by lightning strikes.
Check for lightning strikes:
1. Some inductive lightning strikes may be far away from the site, and the lightning strike points may not be located on the onsite device.
2. Components are damaged, PV modules are broken, or the junction box is bulged. This may be caused by local lightning strikes.
Check whether there are blackouts caused by lightning strikes around the inverter.
How to prevent:
1. Ensure that the ground points of each PV module and support are properly connected to the ground bar and are properly grounded. Check the ground points periodically.
2. The shells of the SUN2000 in the combiner box are grounded properly and are properly grounded to the ground grid.
3. Lightning protection devices are properly installed. Some small power plants are equipped with large surge protection modules. Inductive lightning may cause device damage. However, the surge protection modules may not work. Therefore, you can design a good surge protection capability based on the actual situation.
