Solar grid tie string inverter converts solar panels DC output electricity To AC electricity, it can handle 6-10 solar panels connected in series, so it stands for 1 string.
For large solar array you can use multiple string inverters and connect all together with one AC output for your loads. By using grid tie string inverters such way, you can make use of different tilt and azimuth angles that can be applied even for each sting, so getting maximum yield. In addition, increasing the solar array reliability as for example the shadow in one string panel will not affect the efficiency of other strings.
Selecting the correct solar grid tie inverter will increase your solar system efficiency due to its important role, it consisted as the brain of the whole solar system and here are some factors to be well considered:
Try to select the string inverter efficiency to be closer to 100%, in the market you will find efficiencies in the range (96-99%). Efficiency percentage value represents how much energy to be lost during converting DC power to AC power.
Try to select the grid tie string inverter with simple and easy installation, the inverter should have brackets and all accessories to assist only one person to install. It will be great if the inverter can be installed behind the string modules, so can reduce connection cable length, and save some costs. Also, if the string inverter can be wired via single MC4 to be something like plug and play installation. Just we need to streamline installation process so reduce time and cost.
Inverter strength and resistance to environmental conditions
First thing to check is the string inverter protection degree, called NEMA rating, it reflects inverter capability to withstand weather condition like dust, rains, ..etc. Of course, the higher the better, so try to get IP67 or IP69. Also check solar inverter capability to withstand high environmental temperature. If the inverter will be installed near to a sea/river coast, then take care the inverter should be coated with salt resistance material for more protection and longer life span.
This is a smart feature that allow you to connect the grid tie string inverter to the internet, then be able to know inverter output and system generation and many other parameters from your PC. This system will provide alarms in case of unnormal conditions like exceeding inverter temperature threshold, and so on. So, you will be able to fully monitor and control your whole solar system remotely via the string inverter connectivity feature. In addition, the inverter connectivity system will store information, so you can recall and revise any historical data that assist you well understanding your system previous problems, productions data, ...then achieving optimal operation and correct planning for the future.