The increase of powers, elevation of the voltages and needs to transmit to distances majors every time, turns to the transforming in electrical equipment of the great importance. In the operation of the transforming of power these are subject to thermal, electrical and mechanical efforts, which bring about certain degradation in the aislacin system. The main causes of the phenomenon of degradation of the insulating system are the strong temperatures, I oxygenate, and humidity in combination with the electrical efforts, which act like accelerator of the degradation process. The secondary causes that cause the aging of the insulating system are the mechanical stresses, the acids and muds. An excess of anyone of these efforts can contribute to the degradation process. partial unloadings the process of degradation of the insulating system can evolve until a fault in the power transformer appears, this one can be very harmful. The faults some times happen without no alarm or signal that exists a problem is appearing. But in other occasions there are small indications that indicate the presence of harmful agents or deterioration. The opportune detection of such indications can be the difference between putting under the transformer a repair, replacing a damaged piece or to have a failed equipment with all the serious problems that this would cause. The existence of DPs is as of the problems more frequent than original Author and source of the article appear in the transforming of power