Operation characteristic analysis of same-tower transmission lines and its influence on relay protection

The wide application of same-tower transmission lines has brought new challenges to fault analysis and relay protection operation in power system. In this paper, the diversity of construction form of same-tower transmission lines is introduced. And its operation characteristics, such as strong magnetic coupling and easy occurrence of inter-line fault, are analyzed. Then the influence of same-tower transmission lines on relay protection is studied. The influence matrix of distance protection, zero sequence protection and fault phase selection components is summarized. Finally, from the point of view of protection setting and configuration, power system operation and management, and protection device, several solutions to minimize the influence of same-tower transmission lines are proposed.