Communicating over electric distribution lines

Problems of remote control and metering by carrier transmission over the distribution feeders are considered. The choice of carrier frequencies by the author´s Company for compromise between characteristics of noise (harmonics) and electrical length (standing waves) is explained. Modulation, filtering, and integrate-and-dump detection methods of elimination of harmonic effects are described, with special reference to spikes from SCR-controlled variable-speed motors, and matched filtering of white noise. Propagation problems (and countermeasures) are related to power-factor-correction capacitor banks, critical electrical lengths between dwellings and substation, and distribution transformer leakage reactance.<>