Common faults of inverter and its treatment are summarized

As the testing center of the whole power station, the inverter can be detected by the inverter.

As long as the inverter is in the grid-connected state, the power curve displayed by the monitoring is a normal "mountain" line, which proves that the operation of the power station is stable. If there is any abnormality, the health condition of the auxiliary equipment of the power station can be checked by the feedback of the inverter. Here are the basic problems and solutions:

1. Low insulation resistance: use elimination method. String inverter input side group all pull out, and then connected one by using the inverter switch on the function of testing insulation resistance, detection problem set of strings, find the problem set series, key to check whether there is water dc connector nipple stents or burning-out short sub, you also can check whether the component itself is in the edge shading burning cause components through the frame leakage to the ground.

2. Low bus voltage: if it occurs in early/late hours, it is normal, because the inverter is trying the extreme power generation conditions. If it appears in normal daylight, the detection method is still elimination method, and the detection method is the same as one item.

3. Leakage fault: the root cause of such problems is the installation quality problem, which is caused by choosing the wrong installation location and low-quality equipment. There are many fault points: low-quality dc joints, low-quality components, unqualified installation height of components, low quality of grid-connected equipment or leakage of water and electricity. If similar problems occur, the problem can be solved by finding fault points and insulation work in powder spraying.

4. Dc overvoltage protection: as the components pursue efficient process improvement, the power level is constantly updated and increased. Meanwhile, the open circuit voltage and working voltage of the components are also rising. Temperature coefficient should be taken into account in the design stage to avoid the equipment hard damage caused by overpressure at low temperature.

5. There is no response when the inverter is started up: please make sure that the dc input line is not connected backwards. It is important to read the instructions of the inverter carefully to ensure that the positive and negative terminals are connected after re-pressing. The inverter has built-in reverse connection short-circuit protection, which will start normally after normal connection is restored.

6. Power grid failure:

Grid overvoltage: preliminary prospecting grid overloading (power consumption big work time)/light load, power consumption less rest time work here, early exploration and the health of the node voltage, communication with the inverter manufacturer grid technology for binding energy to ensure the project design in a reasonable range, do not "assume", especially the rural power grids, inverter to the grid voltage, grid waveform, interconnection distance has strict requirements. The problem of over-voltage of power grid is mainly caused by the light load voltage of the original power grid exceeding or approaching the protection value of safety regulation. If the grid-connected line is too long or the pressure connection is not good, the power station cannot operate normally and stably. The solution is to find the power supply bureau to coordinate the voltage or the correct choice of grid connection and strict attention to the quality of power station construction.

Undervoltage of power grid: this problem is consistent with the treatment method of over-voltage of power grid, but if there is an independent phase voltage too low, in addition to the incomplete load distribution of the original power grid, the power loss or circuit break of this phase power grid will also lead to this problem, resulting in virtual voltage.

Overpower/underpower grid: if the normal power grid has such problems, the health of the power grid is very worrying.

No power grid voltage: check the grid connection.

Power grid missing phase: check the missing phase circuit, that is, no voltage line.

7. Last point -- monitoring lap: read the instructions of each equipment correctly, and set up the communication address and time of the equipment. It is a guarantee of stable and effective communication!

8. Power generation guarantee: wipe the board with free space, and the power generation will be "convex".

In fact, for a power station, many problems are not caused by the inverter itself, but by other equipment or installation methods. Therefore, material selection and installation in the early stage also need attention.

The design of tilt Angle azimuth, the design of component spacing, the selection of installation site, the inspection of power grid voltage health and other preliminary work also determine the performance of power station operation and power generation in the following 25 years. It can be said that the overall quality of the power station depends on the material and installation quality of the power station!

Recommended equipment selection for household photovoltaic system:

1. Components: select a-class board, judge based on price, reject low-price and low-quality products, such as defective grid lines.

2. Support: adopt anti-corrosion support, and the components should be at least 30cm away from the ground.

3. Grounding flat steel: it is very important to properly design and configure grounding engineering according to the system size.

4. Dc terminals: very important materials. Poor quality terminals will often cause overheating and melting due to single point contact of terminal cores. Poor waterproof terminals will lead to false short circuit and leakage of electricity between terminals and supports in rainy days. Small make up do not post the burning situation, leave some imagination space.

5. Dc cable: choose the cable model size correctly, and the design honor should not be too small or too large, generally 1.2-1.5 times. Too small load flow is not enough, too large terminal pressure is not good. No "nest line" is allowed.

6. Inverter: select the inverter with high quality. The installation of the inverter must pay attention to heat dissipation. At present, the inverter is installed outdoors with IP65.

7. Ac cable: choose the cable model size correctly, and the design honor should not be too small or too large, generally 1.2-1.5 times. Too small load flow is not enough, too large terminal pressure is not good.

8. Cable bridge frame: a good power station always requires clean line running. Whether it is a bridge frame or a simple fixed way, it determines the beautiful layer and durability of the power station.

9. Ac grid-connected equipment: it is impossible to cut corners, choose the grid-connected switch and lightning protection equipment correctly, and design the grid-connected circuit correctly, so that the system can operate reliably.

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