Modification of the FFTA method for calculating and analyzing the human reliability of maintenance groups in power transmission grids

The probability of the correct performance of the activities required by the system over a given period of time and the working conditions specified by a person is called human reliability. Human reliability is seen in all industries, and it can affect the performance of the system or results in unpleasant events. In electrical power systems, the human errors of maintenance groups are one of the most important factors in the failure of electrical equipment. In this paper, a new method based on the combination of Fault Tree Analysis (FTA) and Human Factors Analysis and Classification System is presented in order to calculate and analyze the human reliability in electrical power systems. In this method, the basic causes (roots) of human errors are comprehensively identified in all aspects. The relationship among the causing roots, and also between the human errors and these roots are established logically. Finally, human reliability can calculate easily. Since the data available in this study are mostly linguistic, the fuzzy logic is used to eliminate the inaccuracy of the evaluation and to improve the FTA technique. The validity and the accuracy of the presented method are assessed by the results of human reliability analysis in Fars Electricity Maintenance Contractor Company as a case study. Results show the accuracy of the proposed method for human reliability analyses of maintenance groups in power transmission grids.