继电保护原理与应用(第三版)3.1-3.5(17)

图3.3以平衡或对称量运行的典型三相电路的相量图。（a） 显示电流和电压降位置和假定方向的电路图。I和V是位置和方向指示器，而不是相量。（b） 显示电流和电压大小及相位关系的相量图。
3.4 Phasor and Phase Rotation相量和相位旋转
Phasor and phase rotation are two entirely different terms, although they almost look alike. The AC phasors always rotate counterclockwise at the system frequency. The fixed diagrams, plotted such as in Figure 3.3b, represent what would be seen if a stroboscopic light of system frequency were imposed on the system phasors. The phasors would appear fixed in space, as plotted.
相量和相旋转是两个完全不同的术语，尽管它们看起来几乎一样。交流相量始终以系统频率逆时针旋转。固定图（如图3.3b所示）表示，如果系统频率的频闪灯施加在系统相量上，将会看到什么。如图所示，相量在空间中看起来是固定的。
In contrast, phase rotation or phase sequence refers to the order in which the phasors occur as they rotate counterclockwise. The standard sequence today is: a, b, c; A, B, C; 1, 2, 3; or in some areas r, s, t. In Figure 3.3b, the sequence is a, b, c, as indicated. The IEEE dictionary (IEEE 100) defines only phase sequence; hence, this is preferred. However, phase rotation has been used over many years and is still in practice.