Determination and Monitoring of the Overhead Electricity Transmission Cables Sag

Based on the increased need in the last decade to accurately estimate sag value in overhead power transmission lines, a primary method of calculating cable sag value is presented in this article It presents the basic equations starting from the chain equation and the implementation of an offline algorithm developed in Matlab environment to obtain the cable sag value of the overhead power transmission lines. In addition, a minimal hardware/software architecture is presented, which uses in addition to the geometrical data of the power line the information provided by a specialized sensor to measure the horizontal mechanical stress in the cable. Improved versions of this hardware/software architecture, which require additional information from the tilt sensors of the cable, also allow the software implementation of a fault observer. The realtime software implementation for laboratory experiments is based on the LabVIEW programming environment.