The conductivity of composite fibre glass poles

Abstract

The objective of this study is to examine the conductive properties of composite fibre glass poles. The ESB are currently using creosote wooden poles throughout their network for distributing electricity but it is proposed that these poles become composite fibre glass poles. The reason for this is the ESB carried out a socio-economic analysis in relation to creosote wooden poles, as required, to obtain derogation from the European Union as they had imposed a ban on creosote oil type A, the most common type of oil used for the creosote wooden poles. The ESB obtained derogation from the European Union through the Department of Agriculture and continued the use of creosote poles up until June 2001. The socio-economic analysis led the ESB to search for alternatives to creosote wooden poles, including steel, concrete, laminate, hybrid and composite fibre glass poles. The ESB are of the belief that the most suitable poles to replace creosote wooden poles are the fibre glass poles. The ESB import on average 15000 poles a year and spend between €15–20 million a year on poles, which includes purchasing, maintaining, testing the poles and much more, however, by converting to composite fibre glass, this figure will hopefully be significantly reduced over time. Fibre glass composite poles have a life span of roughly 80 years whereas the creosote wooden poles have a life span of only 40 years. The fibre glass poles will require a lot less maintenance than the creosote wooden poles. The fibre glass poles also protect the environment with no leaching of chemical treatments into the soil, ground water or the ecosystems. Although creosote wooden poles are cheaper to purchase than fibre glass composite poles, the life span difference makes the fibre glass poles more financially viable. In this study, conductivity tests were performed on three separate composite fibre glass poles from three different companies located in America (Highland Composites), Canada (RS Poles) & The United Kingdom (Jerol Composites). The samples' conductive properties were tested under four separate conditions, dirty & dry, dirty & wet, clean & dry, and finally clean & wet. It was found that the poles were most conductive under the condition that was dirty & wet yet the samples stayed within the industrial standards imposed by the IEC and other standard organizations. In this study, 75kV were put across 300mm of the samples and the leakage current was measured. Using the appropriate formulae, the conductivity of the various composite fibre glass poles is calculated in theory. Using the log-log graph of the effect of alternating current I of duration T passing from the left hand to the feet, as defined in IEC, publication 60479-1, the extent of the electrical shock that a person would receive from these poles in theory is calculated. It was found that the Jerol Pole sample displayed the optimum conductive qualities, followed by the RS Pole sample and then finally the Highland Pole sample. Although all samples stayed within standard, it was found that when the poles had voltage put across them in their most conductive state that a person would receive a shock but it would be insignificant. Were a person to come in contact with the Jerol Pole, he/she would receive an even less significant shock to those who came in contact with the other samples in the same conditions. Therefore, it was found the superior pole was found to be the Jerol Pole in terms of non-conductive qualities. After obtaining conductivity reports completed by engineers in the ESB, it is fair to conclude that the creosote wooden poles are much more conductive than the composite fibre glass poles examined in this study. This adds to the list of advantages pertaining to the composite fibre glass poles as opposed to the creosote wooden poles. Although the Jerol Poles displayed the best qualities in terms of conductivity, the ESB have decided to purchase their poles from RS Poles in Canada, as they were the best poles when considering other important qualities of the pole, and it also complied with the Industrial Conductivity Standard.