Photovoltaic (PV) reverse connection faults can occur in solar power systems, leading to decreased efficiency and potential damage to the system. These faults are particularly critical in hybrid solar inverters like the Sungrow SH15/20/25T models. This blog post provides a detailed guide on how to troubleshoot and resolve PV reverse connection faults in these inverters, ensuring they continue to operate efficiently and safely.
## Understanding PV Reverse Connection Fault
A PV reverse connection fault happens when the positive and negative cables from the solar panels (PV strings) are connected in reverse to the inverter’s PV input terminals. This can cause the inverter to shut down to prevent damage. The Sungrow SH15/20/25T inverters are equipped with fault detection for such issues, typically indicated by error codes 28 and 29, which correspond to PV1 and PV2 inputs, respectively.
### Symptoms of PV Reverse Connection Fault:
– The inverter displays an error code related to PV reverse connection (28 or 29).
– Reduced or no power output from the affected PV strings.
– Automatic shutdown of the inverter.
## Step-by-Step Troubleshooting Guide
### Step 1: Identify and Confirm the Reverse Connection
To begin resolving a PV reverse connection fault:
– **Check the Polarity**: Inspect the connections at the inverter for the PV strings indicated by the error codes. Ensure that the positive (+) and negative (-) wires are connected to their respective terminals correctly.
– **Use a Multimeter**: Measure the polarity of the string outputs when the inverter is turned off to confirm if they are indeed reversed.
### Step 2: Correct the Polarity
If you confirm that the polarity is reversed:
– **Disconnect the DC Switch**: Turn off the DC switch for the affected strings to completely disconnect them from the inverter.
– **Wait for String Current to Drop**: Ensure that the string current drops below 0.5 A before making any adjustments. This is crucial to avoid any electrical hazards or further damage.
– **Adjust the Polarity**: Reconnect the positive and negative wires to their correct terminals.
– **Reconnect and Test**: Once the cables are correctly connected, turn on the DC switch and check the inverter display to ensure that the fault has cleared.
### Step 3: Contact Sungrow Support
If the fault persists even after correcting the polarity:
– **Contact Sungrow Customer Support**: Provide them with details of the fault, the steps you have taken to resolve it, and any observations post-correction.
– **Technical Assistance**: Sungrow may offer additional troubleshooting steps or suggest a service visit to ensure that the issue is thoroughly resolved.
## Conclusion
PV reverse connection faults are a serious concern but can be effectively managed with careful troubleshooting and correction. For owners of Sungrow SH15/20/25T hybrid solar inverters, following the steps outlined above will help quickly resolve such issues and minimize downtime. Always ensure safety when handling electrical components, and if in doubt, seek assistance from a professional technician. Regular checks and maintenance of your solar system’s wiring and connections can prevent such faults and ensure optimal performance of your solar power system.
