The WLD-1678C anti-islanding protection and control device is a core safety equipment for new energy grid-connected systems (such as photovoltaic, wind power, energy storage, etc.). It is mainly used to detect and isolate the "islanding effect" – that is, when the grid is de-energized due to faults or maintenance, distributed power sources (such as photovoltaic inverters) continue to supply power to the local grid, forming a dangerous state of independent operation. The device ensures personnel safety, equipment stability, and grid power quality by rapidly disconnecting the grid connection point, and is widely used in photovoltaic power plants, microgrids, industrial power distribution, and other fields.