This master’s thesis presents the problem of calculating electrical distances for the case of the network of continental Europe, which part is also the Slovenian transmission network. At the beginning we find out why smaller networks are connected into larger interconnection network and how the electricity grid is distributed in Europe. Next we describe models of elements used in the calculations. Because electrical distances can be obtained from the inversion of nodal admittance matrix, we look at how to construct it. In the following, we ask ourselves if it is necessary to invert the entire admittance matrix, since the inverse of the large matrix is time consuming. We figure out that with the DD algorithm we can calculate the diagonal elements of the inverse matrix without inverting the entire admittance matrix. We look more closely how DD algorithm work and how we can use it in our calculations. The calculations were performed using our own program, developed with Delphi 7 software package, which is based on Pascal programming language. Below we describe problems that this software package brings out and provide possible solutions with practical examples for easier understanding. Finally, we present a graphical interface and possible calculation settings.