常见问题 - Zhejiang Hyxi Technology Co., Ltd.

Yes, the calculation of the inverter's DC input can be done following the provisions of the photovoltaic power station design code "GB50797". This involves considering both the open circuit voltage of the modules (determining the maximum number of components that can be connected in each string) and the working voltage of the modules (taking into account the MPPT efficiency of the inverter). The actual calculation can be tailored based on the specific conditions and requirements of the installation.

Components with different power ratings should generally not be connected in series because their power ratings determine their working currents, and when connected in series, the entire string will be limited by the smallest component's current. However, in cases where the power difference is relatively small, it might be possible to connect them in series. The larger the power difference between the components, the greater the difference in current, making it more challenging to achieve proper string operation. It is recommended to avoid significant power differences when considering series connections to ensure efficient and safe operation.

In the presence of a voltage parallel mismatch, the MPPT will track the maximum power point differently for each string. The lower voltage will have an impact on the higher one, thus affecting the overall output power.

To determine the circuit breaker size needed for a 6kW inverter operating at 220V, you would need to consider a 1.1 times overload. This would result in a maximum AC output power of 6.6kW, which corresponds to a current of 30A. Typically, a circuit breaker with a rating of 1.5 times the rated current is chosen. Therefore, you would require a circuit breaker with a rating of 45A or more to handle the output of the 6kW inverter safely.

When it comes to power stations, whether they operate as a surplus power grid or a full grid connection is determined by the location of the grid connection point. This can be either at the front end or back end of the load, and it's completely independent of the inverter, meaning there's no need to change it. However, if you had previously applied for a full grid connection, you will need to reach out to the power supply company again to reapply for the surplus power grid connection.

1. Generally, once the power grid restores its normal operation, the inverter will automatically reconnect to the grid. However, if the issue persists:

2. Verify if the power grid is reliably supplying electricity.

3. Inspect the AC wiring to ensure all connections are secure and properly tightened.

4. Double-check that the AC cable is correctly connected to the appropriate terminal (ensuring the live wire is not mistakenly connected to the neutral wire).

5. Confirm that the AC circuit breaker is closed and functioning properly.

1. In general situations, once the power grid returns to normal, the inverter will automatically reconnect to the grid. However, if the problem persists:

2. Measure the actual voltage of the power grid to confirm if it is indeed lower than the set value. If so, please contact the local power company for a solution.

3. You can also use the App to check if the protection parameter settings are according to the requirements.

4. Inspect the AC wiring to ensure all connections are secure and properly tightened.

There are two possible situations:

During summer, the power generation of photovoltaic power plants may not be as high as during clear spring or autumn days, mainly due to the adverse impact of sustained high temperatures on the components. As the temperature rises, the output power of the modules decreases, leading to a reduction in power generation of approximately 0.44% for every degree of temperature increase.

If the power station's components are oversized in comparison to the inverter capacity, excessive output power may cause the inverter to operate at a reduced capacity. To address this, it is essential to check whether the inverter's output parameters fall within the normal range and take preventive measures to avoid derating operations, which can result in decreased power generation.

Typically, the total power output of the solar panels can exceed the inverter's rated capacity, as long as the voltage of each string remains below the inverter's maximum system voltage. A 6KW inverter with 2 MPPTs can be configured with one or two strings of solar panels, and in either case can produce up to or even more than the rated power of 6KW.

Solution

System

[String & Hybrid inverter] Can the inverter's DC input be calculated based on the rated voltage of the components?

[String & Hybrid inverter] Can components of different power ratings be connected in series? If so, can they be connected in series with only a small difference in power? What is the acceptable power difference for series connection?

[String & Hybrid inverter] In a scenario where there is an error in the open-circuit voltages of two strings under MPPT, should the MPPT track the high voltage or the low voltage?

[String & Hybrid inverter] What is the appropriate circuit breaker size for a 6kW inverter that runs on 220V?

[String & Hybrid inverter] If I want to change the power station to self-consumption with surplus power grid connection, do I need to replace the inverter?

[String & Hybrid inverter] How should one handle power loss in the power grid?

[String & Hybrid inverter] How to deal with the low voltage of the power grid?

[String & Hybrid inverter] Why does power generation decrease when the weather is better?

[String & Hybrid inverter] If the voltage of each solar panel string stays within the inverter's limit, can it produce more power than the inverter's rated capacity? (For example, a 6kW inverter with 2 MPPTs, each capable of handling up to 3