Overhead Power Transmission Wires

OW, OPTW 

 Overhead power transmission wires (OW, OPTW) are structures used to transfer electrical energy over long distances by land. The main structural elements of this system are the overhead wires, cables, pylons, insulators and line fittings. Grounding supports are also fitted at the top of the pylons in order to protect from electrical surges and storms. The grounding supports also provide structural benefits, keeping the cables at a certain distance from the ground. Insulators keep the wires making contact with the grounding supports. In some cases, the overhead wires with insulators and line fittings are attached to the brackets on engineering structures.

The main advantage of OPTWs is their relatively low price in comparison to standard underground cables. They are also a lot easier to maintain as no excavation work is required to replace the wires and visual inspections are a lot easier to carry out. This being said, OPTWs are not without drawbacks:

◦ wide strip of alienation: there should be no structures or vegetation in the vicinity of the powerlines. If the grid runs through a forest; all trees within proximity to the pylons are required to be cut down. 

◦ no security from external influences: such as falling trees or theft of the line wires. in spite of efforts to minimize this, overhead lines are also affected by lightning strikes. Due to the vulnerability, each overhead line is equipped with a secondary cable to act as a backup;

◦ aesthetic unattractiveness; This is the main reason power companies are switching to ground cables to provide power to cities.