Introduction to Electrical Power and Power Electronics

116 Introduction to Electrical Power and Power Electronics

The above matrix equation leads to

V

a

0

= 1/3{450∠0 + 450∠−90 + 900∠−225} = 87.75∠−225°

V

a

+

= 1/3{450∠0 + 450∠30 + 900∠15} = 590∠15°

V

a

−

= 1/3{450∠0 + 450∠150 + 900∠−105} = 222.3∠−105°.

The positive sequence voltage is 590 ÷ 690 = 0.855 pu of the rated voltage,

which will produce 85.5% flux rotating in the positive direction. The negative

sequence voltage of 222.3 ÷ 690 = 0.322 pu will produce 32.2% of rated flux

rotating in the reverse direction. The zero sequence voltage of 87.75 ÷ 690 = 0.127

will produce 12.7% of rated flux not rotating at all (alternating but stationary in

space).

If the ...