In the article, the problems, connected with reflectometric fault points definition and points of obstacles occurrence on power transmission lines, are considered. The method based on reflectogram comparison is considered. The authors show that this method does not always give good results. It is connected with change in time of physical parameters of the supervised line. Using adaptation of the current reflectogram to an exemplary one by means of time scaling is preferable. For the implementation of scaling, the reflectogram should be in a continuous form, but the taken reflectogram is presented in a discrete form. Therefore, the authors offered to apply piecewise and linear interpolation to obtain the current reflectogram in a continuous form. Scaling is carried out by changing the scaling coefficient by one of the known algorithms of optimization. Due to the exact combination of exemplary and scaled current reflectogram, it is possible to increase efficiency of the reflectogram comparison method.