2.2.1 Positive Phase Sequence

In case of a positive phase sequence, the voltage on all the three lines of three-phase supply cycles through 360°, where L2 phase lags L1 by 120° and L3 phase lags L1 by +240°. The sequence L1-L2-L3 is termed as a positive phase sequence.

Figure 2-1a shows the positive phase sequence of three-phase supply, where the L1, L2 and L3 phases attain their respective peak voltages periodically, one after the other in the sequence.