It is important to know how to solve the problem of ac inverter. Today, Xindun will discusse the problem of ac overpressure of inverters.
In principle, the pv inverter itself does not generate voltage, and the voltage displayed by the inverter is partly from the photovoltaic module, called dc voltage, and partly from the grid, called ac voltage. What if the grid-connected inverter displays "ac overvoltage problem"?
According to the relevant regulations, the PV grid connected inverter must work in the specified voltage range. It can be monitored in real time and synchronize with the voltage of the power grid. When the inverter detects the voltage of the power grid (AC voltage) beyond the specified range, the inverter must jump off and stop work, in order to ensure the safety of the equipment and protect the operator personal safety.
When there are AC overvoltages in inverters, there are three situations.
Situation 1: The grid is too far away to cause voltage rise.
The distance between the grid-connected inverter and the grid is too far, which will lead to the voltage difference on the ac terminal side of the inverter increasing. When the grid-connected voltage range is exceeded, the inverter will show the over-voltage of the grid. In addition, the cable used by the inverter is too long, too thin, winding or unconventional material, which will cause the increase of the voltage difference at the AC terminal of the inverter. So the cable selection and the rational distribution of the cable are especially important.
In this case, we should first check whether the grid distance is too long, it is best to choose the near grid scheme; secondly, check the cable distribution and cable quality, select the reasonable wiring way and the qualified AC cable.
Situation 2: Multiple inverters focus one access point
In fact, the rise time of domestic photovoltaic power generation is not long, and the power supply bureau has not much experience when selecting inverters and connected to the network, and sometimes it will appear unprofessional or unconsidered. The frequently occurring situation is to connect a number of single-phase inverters to the same phase, which can easily lead to unbalance of the voltage of the power grid, and the voltage of the grid is raised, and the grid voltage is too high.
This situation is relatively well resolved. It is necessary to consider the capacity of the project should be allocated to the three phases of the power grid, and select multiple points to connect to the network.
Situation 3: The capacity of PV installed in the same area is too large
As the national policy is getting better and better, the financing channels of photovoltaic finance are expanding, and many people are scrambling to install it, so that there may be too many PV installed capacity in the same area (a transformer\'s power supply range or area), and the power grid load digestibility is not enough. Because the electric energy produced by the photovoltaic system can not be consumed near and can not realize the long-distance transportation point, the natural grid voltage will increase continuously, and the inverter also shows that the grid voltage is too high.
The solution to this situation is:
1, PV power station reduction capacity
2, Transformer compatibilization
3, Do a good job of prevention: early investigation, power grid assessment, appropriate grid connection capacity (best method).
As the "key gentleman" of the whole system of photovoltaic system, the good or bad of the inverter directly determines the advantages and disadvantages of the system. It is also very important for the installation and maintenance of the photovoltaic system to master and understand the tricks to solve the inverter fault.
Xindun new energy, professional inverter manufacturers, to provide you with reliable, safe and efficient photovoltaic inverter, provide professional, timely and effective pre sales and after-sales service for your power station escort!