The Reliability and Power Quality Performance of Overhead Lines – with reference to the Electrical Properties of Wood and Covered Conductors

In the information technology age, users of electricity services require both better reliability (fewer interruptions of supply) and better power quality (fewer disturbances, particularly voltage sags). The paper shows that the best way to reduce the frequency of interruptions and voltage sags is to reduce the number of faults on the distribution utility’s low voltage and high voltage lines. Most utilities already use lines with wood poles and crossarms with the wood’s electrical properties used to good effect. But a trend to “maintenance-free” designs will inevitably increase the frequency of faults, particularly those caused by direct and nearby lightning and by wind-effects. The most effective way to reduce the frequency of faults on existing overhead lines would be to develop an acceptable technology for costeffective retro-fitting of insulating covers on those spans of existing lines near trees.