Definition
The standard method of generating and transmitting bulk electric power, using three conductors (phases) carrying sinusoidal currents of equal magnitude but displaced 120 degrees apart in time. Three-phase systems are used exclusively for bulk transmission because they deliver constant instantaneous power (unlike single-phase, which pulses at twice line frequency), require 75% less conductor material per MW transmitted than single-phase, and efficiently drive large rotating machinery. Generator stators, transformer windings, transmission lines, and large industrial loads all use three-phase configurations.
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Topic Deck
Electrical Engineering Fundamentals
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Source
FERC Pro Forma OATT / LGIP