Ongrid solar inverters have high working efficiency and reliable performance. They are suitable for installation in remote areas where no one is maintaining or on duty. They can maximize the use of solar energy, thus improving the efficiency of the system. Below I will introduce to you the installation precautions for installing grid-connected inverters.
1. Before installation, you should first check whether the inverter has been damaged during transportation.
2. When selecting an installation site, make sure there is no interference from other power electronic equipment in the surrounding area.
3. Before making electrical connections, be sure to cover the photovoltaic panels with opaque materials or disconnect the DC side circuit breaker. When exposed to sunlight, photovoltaic arrays will generate dangerous voltages.
4. All installation operations must be completed by professional technicians only.
5. The cables used in the photovoltaic system power generation system must be firmly connected, well insulated and of appropriate specifications.
6. All electrical installations must meet local and national electrical standards.
7. The inverter can only be connected to the grid after obtaining permission from the local power department and after professional technicians have completed all electrical connections.
8. Before performing any maintenance work, you should first disconnect the electrical connection between the inverter and the grid, and then disconnect the DC side electrical connection.
9. Wait at least 5 minutes until the internal components are discharged before performing maintenance work.
10. Any fault that affects the safety performance of the inverter must be eliminated immediately before the inverter can be turned on again.
11. Avoid unnecessary circuit board contact.
12. Comply with electrostatic protection regulations and wear an anti-static bracelet.
13. Pay attention to and obey the warning labels on the product.
14. Conduct a preliminary visual inspection of the equipment for damage or other dangerous conditions before operation.
15. Pay attention to the hot surface of the inverter. For example, the radiator of power semiconductors will still maintain a high temperature for a period of time after the inverter is powered off.
The DC input of the photovoltaic grid-connected inverter mainly includes the maximum input voltage, starting voltage, rated input voltage, MPPT voltage, and the number of MPPTs.
Among them, the MPPT voltage range determines whether the voltage after the photovoltaic strings are connected in series meets the optimal voltage input range of the inverter. The number of MPPTs and the maximum number of input strings for each MPPT determine the series-parallel design method of photovoltaic modules. The maximum input current determines the maximum string input current value of each MPPT, and is an important determining condition for photovoltaic module selection.
The AC output of the photovoltaic grid-connected inverter mainly includes rated output power, maximum output power, maximum output current, rated grid voltage, etc. The output power of the inverter under normal working conditions cannot exceed the rated power. When sunshine resources are abundant, the inverter's output can work within the maximum output power for a short period of time.
In addition, the power factor of the inverter is the ratio of the output power to the apparent power. The closer this value is to 1, the higher the efficiency of the inverter.
The protection functions of photovoltaic grid-connected inverters mainly include DC reverse polarity protection, AC short circuit protection, anti-islanding protection, surge protection, AC and DC over-voltage and under-voltage protection, leakage current protection, etc.
1. DC reverse connection protection: prevent AC short circuit when the positive input terminal and negative input terminal of the inverter are reversely connected.
2. AC short-circuit protection: Prevent the AC output side of the inverter from short-circuiting. At the same time, when a short-circuit occurs in the power grid, the inverter protects itself.
3. Anti-islanding protection: When the power grid loses power and loses voltage, the inverter stops working due to the loss of voltage.
4. Surge protection: Protects the inverter from transient overvoltage.