Power system fundamentals - Wind Power Integration: Connection and System Operational Aspects - page 37

A

V AN V AB

B

Source

V BN

C

N

Figure 2.17 Three-phase supply

V CN

V AB

30 °

30° 60°

V AN

V BN

Figure 2.18 Phasor relationship between line and phase voltages

Adding the corresponding phasors of Figure 2.18 results in the following
relation for line voltage magnitude in terms of phase voltage magnitude:

p V AN

V AB ¼

In general, for a balanced three-phase supply:

p V PH

V L ¼ ð 2 : 15 Þ

2.4.4 Balanced star-connected load
The connections for a star-connected load are shown in Figure 2.19.
In general, for a balanced, star-connected load:
V L ¼

p V PH
I L ¼ I PH
P ¼ 3 V PH I PH cos f ¼ p V L I L cos f