Now PV Grid-connected power generation is becoming more and more popular, ordinary people home can see the figure of photovoltaic power station.
However, for the common people, the PV grid-connected system, especially the grid-connected inverter is still not as familiar as the TV refrigerator, and even some of the installation of the company's technical staff can not do the inverter common failure of the decisive and rapid investigation. Therefore, when the inverter feedback some of the system fault information, people will appear helpless.
Therefore, it is an important condition to know how to solve the fault of inverter and to ensure the normal operation of the inverter. In principle, the PV inverter itself will not produce voltage, the inverter shows a part of the voltage from the PV module, called DC Voltage, the other part from the grid called alternating voltage.
What to do if the ' grid-connected inverter shows the AC overvoltage problem '.
In accordance with the relevant provisions, PV grid-connected inverter must be within the specified voltage range of the grid to work, capable of real-time monitoring and synchronization with the grid voltage, when the inverter detects that the power grid voltage (AC voltage) is out of range, the inverter must stop working to ensure the safety of the equipment and to protect the safety of the operator.
According to the ' clinical experience ' over the years, when the inverter appears AC overvoltage, the following three kinds of situations occur:
Condition One: The grid distance is too far, causing the voltage to elevate Grid-connected inverter to the grid and network distance is too far, will lead to Inverter AC terminal side of the voltage difference, more than the inverter specified on-grid voltage range, the inverter will show the power grid overvoltage.
In addition, the inverter to the network and the use of cable is too long, too thin, winding or material irregularities, etc., will lead to inverter AC terminal voltage difference, so the cable selection and rational use of the layout is particularly important.
In view of this situation first to check whether the grid-connected distance is too long, it is best to select the nearest grid-connected scheme; second, the cable distribution and cable quality, select a reasonable wiring and qualified AC cable.
Case TWO: Multiple inverters focus on an access point The domestic PV power generation actually rise time is not long, the Electricity Supply Bureau has the experience not many in the choice inverter grid-connected, and sometimes may appear unprofessional or is not considered.
It is often the case that multiple single-phase inverters are connected to the same phase, which can easily lead to unbalanced power grid voltages, and the power grid voltage is elevated, which naturally causes the grid voltage to be too high.
This situation is relatively good to solve, we need to consider the project grid-connected capacity allocation to the three-phase grid, select a multiple-point grid.
Situation three: The same area PV installed capacity is too large With the national policy more and more good, the expansion of photovoltaic financing channels, many people are scrambling to install, so there may be the same area (a transformer power supply range or region) PV installed capacity too much, the power grid load digestion capacity is insufficient.
Because the photovoltaic system generated electricity can not be consumed near, and can not achieve long-distance transmission point, the natural power grid voltage will continue to rise, the inverter also appears to show the grid-connected voltage is too high.
The solution to this situation is as follows:
1, PV power Station reduced capacity
2, transformer increase capacity
