Frequency response analysis is an important method of detecting transformer winding deformation. Experienced professionals are able to judge winding deformation accurately by qualitative analysis of the frequency response data atlas. Firstly

the qualitative analysis methods for frequency response data are summarized. Secondly

according to the characteristics of the qualitative analysis

the mathematical morphology is introduced and the quantitative analysis for the amplitude difference is researched. The frequency domain is defined to divide the extreme points of the frequency response data into matched extreme point

shifted extreme point

lost extreme point

excess extreme point and the quantitative analysis for the extreme points is researched. Finally

the block frequency point method is proposed. The main points of the qualitative analysis for frequency response data atlas are mathematically presented with the block frequency point method

and the quantitative analysis for frequency response data is realized. The effectiveness of the method is proved by verification of an example.