ECSE 361 Lecture Notes - Lecture 18: Three-Phase Electric Power, Kirchhoff'S Circuit Laws, Phasor
4 Dec 2017
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Document Summary
The voltages in the three-phase power system are produced by a synchronous generator (chapter 4). In a balanced system, each of the three instantaneous voltages have equal amplitudes but are separated from the other voltages by a phase angle of 120 . The three voltages (or phases) are typically labeled a, b and c. the common reference point for the three phase voltages is designated as the neutral connection and is labeled as n. We may define either a positive phase sequence (abc) or a negative phase sequence (acb) as shown below. The three sources v , v and v are designated as the line-to-neutral voltages in the three-phase system. an o bn cn. An alternative way of defining the voltages in a balanced three-phase system is to define the voltage differences between the phases. The line-to-line voltages can be expressed in terms of the line-to-neutral voltages by applying. Kirchoff"s voltage law to the generator circuit, which yields.
