OPGW stands for Optical Ground Wire. It is a dual-purpose cable used in overhead power lines that combines the functions of a traditional overhead ground wire with the high-speed data transmission capabilities of optical fibers.

The OPGW cable is strategically installed at the topmost position of a high-voltage transmission tower. Its metallic outer layer acts as a ground wire, shielding the power conductors from lightning strikes and providing a path for fault currents. Simultaneously, the optical fibers protected within the cable's core enable telecommunications, remote monitoring, and control of the power grid.