As an electronic product, a photovoltaic inverter consists of many components. Inverters, also known as power regulators, can be classified into two types, stand-alone power supplies and grid-connected power supplies, depending on the use of the inverter in photovoltaic power generation systems. According to the waveform modulation method, it can be divided into a square wave inverter, a staircase wave inverter, a sine wave inverter, and a combined three-phase inverter. This article mainly introduces the common faults and treatment methods of Guruwatt PV inverters and the precautions for maintenance. Follow the specific instructions of Xiao Bian.
1, low insulation resistance
Use exclusions. Unplug all the strings on the input side of the inverter, and then connect them one by one. Use the function of the inverter to detect the insulation resistance, detect the problem strings, and then check whether the DC connectors have flooding short-circuit brackets after finding the problem strings. Alternatively, the shorting brackets can be melted and the components themselves can be checked to see if the components themselves have black spots burned at the edges and the components leak to the ground through the frame.
2, the bus voltage is low
If it appears in the early/late hours, it is a normal problem because the inverter is trying to limit the power generation condition. If it is in the normal daytime, the detection method is still the exclusion method, and the detection method is the same as the 1 item.
3, leakage current failure
The root cause of this kind of problem is the installation quality problem, which is caused by choosing the wrong installation site and low quality equipment. There are many points of failure: low-quality DC connectors, low-quality components, unsatisfactory installation height of components, low quality of grid-connected equipment, or leakage of incoming water. Once similar problems occur, you can find out the Good insulation work to solve the problem, if it is the material of this province can only replace the material.
4, DC overvoltage protection
With the pursuit of high-efficiency process improvement of the components, the power level is continuously updated, and the open circuit voltage and the operating voltage of the components are also rising. The temperature coefficient must be considered in the design stage to avoid overvoltage in the low-temperature conditions and hard damage to the equipment.
5. The inverter does not respond to power on
Make sure that the DC input circuit is not reversed. Generally, the DC connector has a foolproof effect, but the crimping terminal has no fool-proof effect. It is important to carefully read the inverter instructions to ensure that the positive and negative terminals are crimped. Inverter built-in reverse short-circuit protection, normal start after restoring normal wiring.
6, power grid failure
Overvoltage in power grid: The work of pre-investigating power grid heavy load (large working hours for power consumption)/light load (reducing power consumption time) is reflected here, and the health status of voltage points at the outlets is surveyed in advance, and the inverter manufacturers Communicating the situation of the power grid and combining technology can ensure that the project design is within reasonable limits. Do not “take it for grantedâ€, especially for rural power grids, inverters with grid voltage, grid-connected waveforms, and grid-connection distances are all strictly required. The majority of power grid overvoltage problems occur because the original power grid light load voltage exceeds or approaches the safety protection value. If the grid connection line is too long or the pressure connection is not good, the line impedance/inductance is too large, and the power station cannot operate normally. The solution to the problem is to find the power supply bureau to coordinate the voltage or to correctly select the grid connection and strictly control the quality of the power station construction.
Grid undervoltage: This problem is consistent with the grid overvoltage treatment method. However, if an independent one-phase voltage is too low, in addition to the original grid load distribution is incomplete, the phase grid power loss or open circuit can also lead to the problem. Virtual voltage.
Grid over-frequency: If the normal grid has such problems, it proves that the grid health is very worrying.
The grid has no voltage: check the grid connection.
Grid phase missing: Check for missing phase circuits, ie no voltage lines.
7, monitoring lap
Correctly read the device manuals, crimp the type circuit, connect the devices, and set the communication address and time of the device. This is to ensure the stable and effective communication.
8, power generation guarantee
When the board is wiped, the amount of power generated is "convex" and it rises.
1. Before performing any maintenance work, first disconnect the inverter from the electrical grid, and then disconnect the DC-side electrical connections.
2. Wait at least 5 minutes until the internal components have been discharged to perform maintenance work.
3. Any fault affecting the safety performance of the inverter must be immediately ruled out before the inverter can be turned on again.
4, to avoid unnecessary circuit board contact
5. Observe the static protection regulations and wear an anti-static wristband.
6. Observe and follow the warning signs on the product.
7. Visually inspect the equipment for damage or other dangerous conditions before operation.
8. Pay attention to the thermal surface of the inverter. Power semiconductor heat sinks, for example, maintain a relatively high temperature for a period of time after the inverter is powered off.
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