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.<
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