Total environmental protection of woodpole overhead lines

Woodpole overhead lines (OHL) are by their very nature open to everything the environment can throw at them. From ground level to the conductors the system has to withstand mechanical and biological forces that cause many headaches to OHL designers and supply customers alike-not to mention the emergency repair teams that bear the initial brunt of any major catastrophe. Ground conditions affect foundation capability as well as fungal growth and pole rot. Wind loads affect the pole and conductors as well as any inconveniently planted trees that tend to fall onto the lines. Wind blown debris causes electrical shorts as does conductor clashing. And that is before the 'real' weather such as lightning, freezing rain, ice and wet snow. The design assessment of overhead lines requires the input of the likely loads that a line will suffer. This paper looks at how these mechanical and electrical loads can be determined both from historical data and in light of climate change.