ELECTRONIC DEVICE FOR ONLINE MONITORING OF THE MOISTURE CONTENT OF THE PAPER OF A POTENTIAL TRANSFORMER SUBJECTED TO OVERLOADING, DIAGNOSIS OF THE SAFE OPERATING TIME THEREIN, AND CORRESPONDING METHOD.

摘要

The invention relates to an electronic device designed to determine online the moisture content of the paper, the bubble-generating temperature, and the loss-of-life percentage of column-type potential transformers. The diagnosis is performed by way of input data which combine the information collected in real time concerning the actual state of the transformer and the information programmed offline concerning the specific design features of the transformer and the state of the paper-oil insulating system. The device comprises communication software enabling all the diagnosis values to be displayed from a remote computer in real time, as well as a graphic interface comprising an additional diagnostic module, designed to be used as a tool to assist in the decision-making process for the management of the transformer load, which uses three mathematical models obtained experimentally, simulating the thermal and dimensional conditions of a potential transformer, obtaining a dynamic estima te of the migration of the moisture which is more accurate than static equilibrium curves, the models programmed in the microcontroller estimating the overload level and its application time in order to continue safely operating the transformer in overload conditions, at the same time the computational tool estimating the maximum hot spot temperature reached during the period of time in which the transformer remains in overload, and calculating the loss-of-life percentage caused by the increase in temperature.