Efficient fault detection of distribution transformers has great worth when installation of distribution transformers in the field is taken into account. Computer software has been developed which makes it possible to detect the region of fault location and evaluate the strength of insulation puncturing. It is capable of locating the position of fault along with total percentage of insulation breakdown region. Different evaluation tests are performed which are capable to recognize not only visible faults but also those faults in the windings of distribution transformers which cannot be captured. Such kinds of faults in transformers generally pass the impulse test but when they are installed in the field they are subjected to cause the insulation failure of windings. The evaluation techniques remarkably cop up with such kind of insulation breakdowns and present a good quality approach of evaluation for undesired dominant frequencies. With the help of this research a new method of impulse testing can be introduced. The scope of this research is to facilitate the transformer designers and manufacturers to improve their designing techniques of insulations which is not yet introduced.