This work aims the reviewing of the models of determining the aging of solid insulation of power transformers. For a better understanding of the discussed topic, it begins with a brief overview of the constituent parts and operation works of power transformers highlighting the importance of this equipment in the transport of energy. It has been a bibliography review, adding the difficult that most of the documents are written in English. The bibliography has principally treated of mechanisms of aging power transformers with special interest in the degradation of solid insulation, this is the insulating paper stayed between the windings of the transformer as it is often the element that determines the life of a transformer. In this sense, it has been reviewed developments related to the degree of polymerization of the paper and the creation of furans in oil studies. After the bibliography review, it has been developed an application that can interact with an Excell book and Matlab Executable that we have called “Transformer Life&Care” that is available to analyze the data provided by the Electrical Engineering Department of Universidad Carlos III de Madrid, to get the most representative factors in the degradation of paper and view the dependence of these factors with different temperatures and humidity for different oxygen concentrations. Upon obtaining the results through the application, we have compared these results with those obtained by other researchers, especially those obtained by Lelekakis and his team because the test performed are very similar to those performed by the Electrical Engineering Department of Universidad Carlos III de Madrid, obtaining results accordance to other researchers.