Which problem solves alternating current

Nowadays, photovoltaic on-grid power generation is becoming more and more popular, and ordinary people can see the photovoltaic power plant in real time. For people, however, the photovoltaic grid-connected system, especially the grid-connected inverter, is still not as well known as the TV refrigerator. Even some technicians from the installation company cannot fix the usual faults of the inverter. Determine quickly.

Therefore, if the inverter returns some system fault information, everyone will be helpless. Therefore, understanding the tips for solving inverter faults is an important prerequisite for ensuring normal inverter operation.

In principle, the PV inverter itself does not generate any voltage. The voltage displayed by the inverter comes from the PV module, called DC voltage, and the other part comes from the grid, called AC voltage. What to do if "Inverter with grid connections shows AC overvoltage problem".

According to the relevant regulations, the grid-connected PV inverter must work within the specified grid voltage range, be monitored in real time and synchronized with the grid voltage. If the inverter determines that the grid voltage (AC voltage) is outside the specified range, the inverter must be tripped to ensure the safety of the device and the personal safety of the operator.

After years of "clinical experience" when the inverter has AC overvoltage, there are no three of the following situations:

Case 1: The mains connection is too far, which leads to an increase in voltage

If the grid-connected inverter is too far away from the grid connection point, the voltage difference on the AC connection side of the inverter increases. If the inverter is connected to the grid voltage range, the inverter displays the grid overvoltage. In addition, the cable used by the inverter to connect to the grid is too long, too thin, tangled or the material is not compliant, which increases the voltage difference at the inverter's AC connection. Therefore, cable selection and rational layout are used. very important.

In this case, first check whether the network connection distance is too long. It is best to choose the next network connection scheme. Second, check the cable distribution and cable quality, choose the appropriate wiring method and qualified AC cable.

Case 2: Several inverters focus on one access point

Domestic PV power generation was not long ago. The utility company hasn't seen much when it comes to choosing inverters to connect to the grid and at times it seems unprofessional or neglected. Often several single-phase inverters are connected to the same phase, which can easily lead to a grid voltage imbalance, and the grid voltage increases, which of course leads to the grid voltage being too high.

This situation is relatively better to solve, you need to consider the project network connection capacity to the three-phase network, choose multi-point network.

Case 3: The PV installation capacity in the same area is too large

As national policies get better and better, photovoltaic funding channels are expanding and many ordinary people are competing for the installation. This can result in too much PV capacity in the same area (the supply voltage area or the area of ​​a transformer). The digestibility of the grid charge is not sufficient. Since the electrical energy generated by the photovoltaic system cannot be used in the vicinity and the remote transmission point cannot be realized, the natural grid voltage will rise continuously and the inverter will show that the grid voltage is too high.

The solution to this situation is:

1. Derating photovoltaic power plant

2, transformer capacity

3. Do good preventative work: examine the network to assess the appropriate on-grid capacity (the best method)

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