In large-scale solar PV plants, why is string inverter technology preferred over central inverters in some cases? 

String inverters handle groups of solar panels (strings) individually. If one string is affected by shading, dirt, or mismatch (like different panel orientations or aging), it only impacts that specific string, not the entire system.

In contrast, central inverters connect many strings together, and a problem in one string (like shading or a faulty panel) can drag down the performance of the whole system.

Thus, string inverters reduce power loss from partial shading or panel mismatch, increasing overall system efficiency and performance.

String Inverter Technology

• A string inverter connects a “string” of solar panels (typically 8–30 panels) to a single inverter. Each string is treated as an independent unit.
• DC power from each string is sent to a dedicated string inverter, which converts it to AC power. Multiple string inverters are used across a large system.

Central Inverter Technology

• A central inverter collects DC power from many strings (hundreds of panels), combined through DC combiner boxes, and converts all the power to AC in one large unit.
• DC strings feed into combiner boxes. Combiner boxes route the power to a single large inverter (hundreds of kW to MW). AC power is sent to the grid or a distribution system.