As the core equipment of solar power generation system, solar inverter is the key device to convert direct current into alternating current. Although the quality of solar inverter is becoming more and more reliable, some faults may still occur during long-term use, such as circuit board failure and transformer failure. If these problems are discovered and solved in time, it will help to ensure the normal operation of solar power generation system. Today, we will introduce common photovoltaic inverter faults and corresponding treatment methods.
1、Solar Inverter Screen Does Not Show
Failure analysis: there is no DC input, the inverter LCD is powered by DC.
Possible causes:
(1) Component voltage is not enough. Inverter working voltage is 100V to 500V, below 100V, the inverter does not work. The module voltage is related to the solar irradiance.
(2) The PV input terminal is reversed. The PV terminal has positive and negative poles, which should correspond to each other and not be reversed with other group strings.
(3) DC switch is not closed.
(4) When the components are connected in series, one of the connectors is not connected properly.
(5) One component is short-circuited, resulting in other strings can not work.
Solution: Measure the DC input voltage of the inverter with a finish meter. When the voltage is normal, the total voltage is the sum of each component voltage. If there is no voltage, test whether DC switch, terminal, cable connector, component, etc. are normal in turn. If there are multiple components, separate separate access test. If the inverter is used for a period of time, no reason is found, then the inverter hardware circuit failure, you can contact the manufacturer after-sales.
2、Solar inverter is not grid-connected, the screen shows that the grid is not connected.
Failure phenomenon: the inverter is not connected to the grid, the screen shows that the grid is not connected.
Failure analysis: the inverter and the grid is not connected
Possible reasons:
(1) AC switch is not closed.
(2) The AC output terminal of the inverter is not connected.
(3) When wiring, the inverter output terminals on the row is loose.
Solution: Measure the AC output voltage of the inverter with a multimeter voltage gear, under normal circumstances, the output terminals should have 220V or 380V voltage, if not, in turn, detect whether the terminals are loose, whether the AC switch is closed, and whether the leakage protection switch is disconnected.
3、Screen display PV voltage is high
Failure analysis: DC voltage is too high alarm
Possible reasons: too many components are connected in series, causing the voltage to exceed the voltage of the inverter.
Solution: Because of the temperature characteristics of the components, the lower the temperature, the higher the voltage. The input voltage range of single-phase string inverter is 100-500V, and it is recommended that the voltage after stringing is between 350-400V. The input voltage range of three-phase string inverter is 250-800V, and it is recommended that the voltage after stringing is between 600-650V. In this voltage range, the inverter efficiency is higher, and power can be generated in the morning and evening when the irradiance is low, but not so much that the voltage exceeds the upper limit of the inverter voltage, causing alarm and shutdown.
4、Screen display PV insulation impedance is too low
Failure analysis: solar system grounding insulation resistance is less than 2 megohms
Possible causes: solar modules, junction boxes, DC cables, inverters, AC cables, terminals and other places there are wires to ground short-circuit or insulation damage, PV terminals and AC wiring shells loose, resulting in water.
Solution: Disconnect the power grid, inverter, in turn, check the resistance of each component wire to ground, find out the problem point, and replace it.
5、Screen display output leakage current is too high
Failure analysis: leakage current is too high
Solution: Remove the PV array input, and then check the peripheral AC power grid. Disconnect all DC and AC terminals, let the inverter power outage for more than 30 minutes, if you can recover on your own, continue to use, if you can not recover, contact the after-sales technical engineer.
6、Screen display grid voltage over range
Failure analysis: Grid voltage is too high. Grid impedance increases, the user side of solar power generation can not be digested, and transmission out of the impedance is too large, resulting in too high a voltage on the output side of the inverter, causing the inverter to protect the shutdown, or derating operation.
Solution:
(1) Increase the output cable, because the thicker the cable, the lower the impedance.
(2) Inverter close to the grid, the shorter the cable, the lower the impedance.
7. AC voltage exceeds the range
Fault cause:
When photovoltaic power generation is connected to the user-side power grid, the voltage at the access point will increase. The greater the internal resistance of the power grid, the greater the increase. The closer to the transformer, the smaller the line resistance, the smaller the fluctuation of the power grid, and the closer to the end of the power grid, the longer the line, the greater the voltage fluctuation. Therefore, when the inverter is connected to the power grid far away from the transformer, the grid working environment of the inverter will become very poor. After exceeding the upper limit of the inverter working voltage, the inverter will report a fault and stop working.
Solution:
1. Try to move the access point of the photovoltaic power station close to the output end of the transformer to reduce line losses.
2. Try to shorten the line length of the inverter AC output end, or use thicker copper core cables to reduce the voltage difference between the inverter and the power grid.
3. Now most grid-connected inverters have AC voltage regulation function. You can contact the manufacturer to widen the AC voltage range to adapt to grid voltage fluctuations.
4. If possible, appropriately lower the output voltage of the transformer.
8. Monitoring problem
Fault cause:
The collector and the inverter are not communicating; the collector is not powered on: signal problem at the installation location; internal reason of the collector.
Solution:
1. Check whether the communication interface between the collector and the inverter is normal, and observe the communication indicator light;
2. Check the local signal strength. A booster antenna is required in places with weak signals
3. Scan the correct collector serial number
4. If the collector does not respond to any connection when there is no problem with the external conditions, it can be considered that the collector has an internal fault.
Time for a New Inverter?
If you're facing unresolved issues with your current solar inverter, it might be time for an upgrade. At Shielden, we provide high-quality solar inverters with long-term warranties to ensure your system runs smoothly. Plus, we offer free solar solutions tailored to your specific needs. Let us help you make the switch to a reliable and efficient inverter today!
