PHOTOVOLTAIC SYSTEM, PROTECTION METHOD, AND INVERTER SYSTEM

This application provides a photovoltaic system, a protection method, and an inverter system. The system includes a controller and two groups of inverters. The two groups of inverters include a positive inverter group and a negative inverter group. The positive inverter group includes at least two inverters: a first inverter and a third inverter. The negative inverter group includes at least two inverters: a second inverter and a fourth inverter. Alternating current output ends of the first inverter and the third inverter are connected in parallel. Direct current input ends of the first inverter and the second inverter are connected in series. Alternating current output ends of the second inverter and the fourth inverter are connected in parallel. Direct current input ends of the third inverter and the fourth inverter are connected in series. The controller obtains a circulating current between at least two inverters whose alternating current output ends are connected in parallel; and when the circulating current is greater than a preset current threshold or a rising rate of the circulating current is greater than a preset rate, controls all inverters whose corresponding alternating current output ends are connected in parallel to undergo wave blocking. This solution can accurately determine that a direct current bus is short-circuited and perform the wave blocking to avoid fault expansion.