Cause 1: There is dust and shading on the surface of PV module
1. Cause analysis
Dust accumulation on the surface of the photovoltaic panel, so that the photovoltaic glass surface light transmission rate decreases, the output performance of the photovoltaic panel decreases, the thicker the dust concentration, the lower the light transmission rate, the lower the sunlight radiation absorbed by the panel, the lower its output performance. The shadow on the module will be used as a load to preferentially consume the energy generated by the PV module (hot spot effect), so that the output power is reduced.
2. Treatment measures
Clean and wipe the PV module regularly to ensure that the surface is clean and can be fully exposed to the sun. Make sure there are no shading objects near the PV modules, and deal with them in time if there are.
Note: It is best to clean the modules in the morning or evening.
Cause 2: Inconsistent PV module selection and installation
1. Reason analysis
The same string, if the series connected components specifications, installation angle and orientation are not consistent, will lead to the input voltage, current is pulled down, affecting the input power.
Several groups in the same MPPT circuit, if the specifications, installation angle and orientation of the connected components are not consistent, it will also lead to the input voltage and current being pulled down and affect the input power. (Remark: Because several groups under the same way are connected in parallel circuit when entering the inverter interior, the voltage is required to be equal. If they are not equal, on the one hand, the machine will collect one group with low voltage when working identification, which will cause waste; on the other hand, it will cause the current loop current inside the machine, which will affect the inverter power generation and service life)
2. Processing method
To ensure that the voltage and current after series-parallel connection are not pulled down, usually, try to adjust the components so that the specifications, installation angle and orientation of the components connected to the same input path are the same; the number and specifications of the components connected to different input paths in the same MPPT circuit are the same.
Cause 3: High grid voltage
1. Cause Analysis
When the grid voltage is too high and exceeds the upper limit of safety regulation, the machine will report that the grid voltage exceeds the limit. If the grid voltage does not exceed the upper limit of safety regulation but is close to the upper limit of safety regulation, the internal voltage regulation function of the inverter will start and automatically reduce the output power to adapt to the grid voltage, resulting in lower power generation.
①When multiple machines are connected to the grid at the same time, the total current behind the grid connection point increases, the voltage drop on the AC side cable becomes larger, and the voltage on the AC side of the inverter also increases.
②The cable between the AC side and the grid connection point is too long and too thin, the resistance value of the cable itself is larger, the voltage drop on the cable will become larger, and the voltage on the AC side of the inverter will become higher.
2. Handling measures
① If there are multiple inverters connected to the grid at the same time, you can turn off one or more inverters to see if the real-time power is higher; if it is higher, you can change the safety regulation to the highest voltage of Chinese standard or separate the machines to the grid.
② Check whether the model, grid connection distance and cable wire diameter meet the standard requirements; if they don't, suggest replacing them with national standard copper wire of larger wire diameter.
Cause 4: Inverter temperature is too high
1. Cause Analysis
Due to the high ambient temperature and unreasonable installation location, the inverter is exposed to direct sunlight. When the temperature of the inverter itself rises to a certain value, the inverter will automatically reduce the power output due to the characteristics of the electronic components themselves, thus reducing the power generation.
2. Judgment method
Check the power curve through monitoring data. If there is a drop in the power curve in summer when the temperature is high at noon, it is likely to be caused by high temperature.
Usually, the inverter detects that the internal temperature reaches about 60℃ when it starts to lower the load; the specific temperature range of lowering for each model may be different, if you can't judge, you can call Goodway after-sale hotline for consultation.
3. Handling measures
Install the inverter in a cool and ventilated place, not facing south as far as possible, and add a sunshade if necessary.
When installing, pay attention to the minimum distance between the top, bottom, left and right of the inverter installation (you can refer to the user's manual for details), and do not install a 360° dead-end shield for the inverter.
Cause 5: Line loss problem
1. Cause Analysis.
DC cable line loss is inevitable, but try to reduce this loss. When the line loss is too large, it will lead to over-voltage drop at the output of the inverter, and the inverter will report an error or even stop working. The choice of cable wire diameter not only affects the power generation, but sometimes there are safety accidents. During the site survey, we found that many customers did not use PV1-F cables with PV certification and the cross-sectional area of the cables used did not meet the requirements.
2. Handling measures
Our string inverter access to the DC side of the cable recommended to choose PV1-F 1 * 4mm2, AC cable selection needs to consider the distance from the inverter to the parallel network.
Cable basics.
① DC cables are mostly laid outdoors and need to be moisture-proof, sun-proof, cold-proof, UV-proof, etc. Therefore, DC cables in distributed PV systems generally choose PV-certified special cables, taking into account the DC plug-in and PV module output current, the current commonly used PV DC cables are PV1-F 1*4mm². ② AC cable is mainly used for the inverter AC side to the AC sink box or AC grid-connected cabinet, in the outdoor installation part of the AC cable needs to consider moisture, sun, cold, UV, and long-distance laying, generally choose YJV type cable; indoor installation of AC cable, need to consider fire and rodent and ant prevention.
③ The grounding cable is mainly for the lightning grounding of user components, the grounding of the component bracket and the grounding of the AC output of the inverter.
Note: The current-carrying data selection criteria for each line type can be found in the chart "YJV three-core power cable continuous current-carrying capacity
Cause six: a group of string connection abnormal
1. Judgment method
Check the DC current of the inverter and compare it with the current value that the string should input. If it is obviously less than the current value that the string should input, use a multimeter to measure the voltage between PV+ and PV- of the PV string, if the measured voltage is 0, it means that the string is disconnected; if the measured voltage is negative, it means that PV+ and PV- are connected backwards.
Reason 7: A way MPPT circuit damage
1. Judgment method
Ensure that the string voltage is higher than the start voltage (using a multimeter to measure the voltage between the string PV + and PV -), only connect the string, see if the machine can start, if not start, indicating that the MPPT circuit is damaged.
Reason eight: time setting error
1. Judgment method
Check the screen display time of the inverter, compare it with the local time, and judge whether it is consistent with the local time. The wrong time setting will cause the calculation time of daily power generation is not a complete day, but it will not affect the total power generation. 2.
2. Processing measures
Change the time to make it consistent with the local time.
