Problem: In a project, the inverter generates an alarm indicating that the phase line of the power grid is short-circuited to the PE. As a result, one PV array stops generating power.
Troubleshooting method: A PV array inverter generates a short-circuit to the PE. The inverter circuit may be faulty. Locate the faulty circuit and isolate and rectify the fault. The inverter will be connected to the grid again.
Troubleshooting procedure:
1. Check the SUN2000 onsite, turn off all switches on the SUN2000 AC side, and measure the insulation of AC power cables to the ground.
Connect the inverter with good insulation to the grid.
2. Locate the faulty inverter. When the AC-side switch of the 14th inverter is turned on, other normal grid-tied inverters generate an alarm indicating that the grid phase line is short-circuited to PE. Repeatedly measure the insulation of the AC-to-ground circuit of the 14th inverter. The result is good.
3. Check the cable connections of inverter 14. It is found that the inverter supplies power to the tracking support, and the cable of the tracking support is connected. Measure the cable of the tracking support and find that the cable of the tracking support does not have sufficient ground resistance.
Remove the power cable from the tracking support from the SUN2000, and SUN2000 14 is connected to the grid.
4. Locate and handle the ground position of the power cable of the tracking support. Connect the power cable to the inverter and restore the ground position onsite.
Conclusion: When the inverter generates an alarm, the grid phase line short-circuits the PE, carefully analyze the AC power cable connection of the inverter, and locate the fault one by one.
