Prerequisites of using similitude for studying distribution networks with a laboratory-scaled grid

Analysis of static regimes distribution networks can be made by using power flow calculations. When real equipment behavior needs to be analyzed inside the grid, proper model of this device is needed for simulating it as well. However, full check might need either connection to the real grid, which may be not allowed in the grid operation, or other techniques may be used as well, e.g., hardware in the loop or down-scaled similar grids in a controlled lab environment. The simulation of a real distribution line through concentrated inductances and resistors avoids use of long cables if the laboratory solution is envisaged. Even so, the real impact in the grid can be better observed if the power of sources and of consumers are high enough for influencing the targeted grid. To avoid this difficult requirement, much smaller sources and consumers can be used if similitude is considered for dimensioning the laboratory network. The paper presents some introductory elements of the approach and shows by simulation that the effect on the lab-scaled grid is satisfactory similar with the results which may be obtained in a real grid, with higher involved powers. Moreover, it is shown that the similarity properties allow proper implementation of lab-scaled grids and the possibility to make analysis in a kW range, while the results can be more generally used, e.g., for hundreds of kW in a real microgrid.