The document discusses applying narrowband power line communication technology in medium voltage smart distribution grids. It describes using existing power lines to transmit data using modulation techniques. A system is proposed using KQ330 modules consisting of a transmitter and receiver to communicate over power lines. The technology can be used for applications like monitoring equipment, automation, and internet access because power lines provide a widespread communication medium at low cost compared to other options. Challenges include impedance matching the communication modules to the power lines.