Yesterday, I got a query regarding the connection of a single phase inverter with the three phase system (grid), so that I am writing this article and hoping this will help everyone to under the basic concept of it. In this article am also covering the basic financial concept of selection of inverter.
There is a vast range of solar inverters available in the market. Although there are many technical parameters for the selection of inverter yet financial parameter plays an important role. While selecting inverter design topology, cabling cost also plays an important role along with the inverter cost, for example with a string inverter there is less requirement of DC cable than the central inverter.
In string inverters both three phase and single phase inverters are available in the wide range. Single phase inverter can be connected to three phase system (Grid) by grouping of three built in order to assemble the three phase system, but one should take care of feed-in apparent power between phase two phases. Power balancers are also used to do the job, however, while using power balancer, the inverter in a group should be mounted in such a way that it provides favorable design for necessary cabling.
This diagram clearly shows that the basic idea of connection for single phase inverter system to three phase system (Grid). A set of string connected to an inverter and this inverter is connected to sub field junction boxes and further these sub field junction boxes are connected to main field junction boxes. Cable sizing for one step to another step will change as the voltage/ current rating changes.
Posted by: Er. Gaurav K. Sharma