Analysis of channel characteristics and modeling of a transformer for PLC-based loss-of-mains concept

Loss-of-mains (LoM) protection is crucial in modern smart grids (SGs), where the number of distributed generation (DG) units has increased making the grids more complex. An LoM situation means that the DG unit(s) is/are still supplying the grid while the connection to the supplying electric power distribution grid is off. This can cause fatal injuries to humans and damages to the equipment. A power line communication (PLC) based LoM concept is introduced, where continuous signaling is used as an indication for the LoM protection from the primary substation through the MV grid, the MV/LV transformers, and each low-voltage (LV) grid to the customers. However, the MV/LV transformers constitute a barrier for the PLC. Thus, in this paper, the channel characteristics and modeling of the MV/LV transformer as a function of frequency in the frequency band from 100 Hz to 1 MHz is analyzed. A model for the transformer is compiled and verified by input impedance measurements.