This article discusses the issue of modeling the time resource of an electrical insulating dielectric to ensure reliable transmission of electromagnetic energy for a power line segment located in a trench in a marine environment, with limited quantitative information about its condition using generalized fuzzy mathematical models of experiment planning theory. Here the actual technical problem is solved to ensure the long-term and stable performance of the transmission lines of electrical energy. Requirements to ensure high performance of power, electric lines of sea ports are determined by the increasing consumption of electrical energy associated with the increasing volume of cargo transported by ships, as well as the tendency to accidents associated with the aging of electrical equipment. To improve the reliability of power supply to seaports and reduce accident rates, new technical and organizational measures are being developed. The task we solve is to develop and build a multivariate mathematical model of that part of the line of force that is hidden from observation, i.e. is not on the surface and has no contact with the atmosphere. When modeling the operating time of a part of a power line that does not interact with the atmosphere, as variables (factors) in this work, we use the measurable characteristics of the power line, which determine this isolation time. The model proposed in this article presents such intensifiers of insulation destruction processes as the line current and the ambient temperature. Given the limited possibilities for obtaining data on the state of isolation of the power line and their insufficient accuracy, in this paper we use the methods of the theory of fuzzy (blurred) sets for computer simulation.