Monitoring Conductor Sags for Dynamic Line Rating Based on Induced Signals in Overhead Ground Wires

The sag information of conductors is important for dynamic line rating. This paper proposes a novel monitoring method for conductor sags based on the current or voltage in ground wires, which is produced by mutual inductance between conductors and ground wires. The devices of this method are easy to install and maintain, and the monitoring effect is not affected by bad weather such as snow and fog. To obtain sag information, a calculation method of induced signals in the ground wires is firstly proposed. Then the sensitivity of the induced signals in the ground wires to the variation of conductor sags is evaluated. The relationship between the induced signals in the ground wires and the sag information is established through neural network. A scaled test model of overhead transmission line is established to verify the proposed method. The accuracy of deduced results is acceptable.