Power System Communications

aerial alarm amplifier amplitude amplitude modulation anode apparatus applied armature arranged attenuation BAKELITE band-pass filter bandwidth battery breaker busbar cable capacitance capacitor cathode channels circuit-breaker coil communication circuit complexor conductors connected contacts control room devices diagram dipole earth fault effect electrical electrons energised equipment facilities feeder filter four-wire circuit frequency modulation grid high-voltage impedance impulses indication inductance inductor input insulated interference intertripping kc/s lamps LC circuit load magnetic Mc/s meter microwave modulation necessary normally operate oscillator output pairs panel phase pilot position possible Post Office potential power line power system power-line protection psophometric voltage pulse quadripole radiation radio ratio reactance receiver rectifier release remote control resistor scheme shown in Fig side band signal slug speech springs substation supply switch switchgear telecommunications telecommunications circuits telemetering teleprinter terminal trans transformer transmission transmitted triode trip tube uniselector unit valve wave wipers wires