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Optical Phase Conductor (OPPC) is a new type of power special optical cable that combines optical fiber units into phase lines. It has dual functions of phase lines and communication, and is mainly used for voltage levels below 110kV in suburban distribution networks and rural power grids. In medium and low voltage power grids, especially distribution lines below 35 kV, some can be installed without grounding wires, so it is impossible to install OPGW. In all power grids, only phase lines are essential. In order to meet the requirements of power monitoring or fiber optic networking, OPPC and OPGW technologies are relatively close. By adding fiber optic units in a suitable way to the traditional phase line structure, it becomes a fiber optic composite phase line.