Presenting a model for quantitative risk assessment of low voltage electrocution in electricity distribution industry using FTA in fuzzy environment

Wide spread of power technology over large areas has paved the way of communication for countless people including professionals and employees involved in production. Power transmission and power distribution have also provided welfare for industrial and domestic consumers. Working with and utilizing this clean energy should be in such a way that causes no hazards to human’s health and well-being. Nonetheless, unexpected events regarding electric shock in which many have died or have permanently been disabled are usually reported. The purpose of the present study was presenting a model for analysing low voltage electric shock based on FTA1 model in fuzzy environment in the electricity distribution industry. In the current study, the causes of low voltage electrocution were analyzed by collecting data from electricity distribution companies followed by initial and library studies. Afterwards, the causes of low voltage electrocution were determined using FTA method. Regarding this fact that the mentioned model (FTA) is a tree hierarchichal model, fuzzy method was used to assign probability weight to root causes. After determining the causes of incidents using FTA model and after finding the basic events, fuzzy logic was adopted to detrmine the probability of occurence for every event and by assigning probability weight to “and” and “or” gates using probabilistic relationships as well as considering the magnitude of their effects in occurence of the main event, the final result was presented. The results reveal that the probability of occurence of low voltage electrocution in electricity distribution industry is 0.109385454 which is a very high level of risk for the employees involved in this vital industry. Therefore, with respect to detrmination of Minimal Cut Set and by adopting control methods, eliminating this path and its effect on the possibility of electrocution have been analyzed. Reliability in low voltage electrocution stands at 0.890614546. By identifying critical path 1 (A 1.1) and by adopting control measures and eliminating it, reliability will improve to 0.927754258 which is a significant increase.