5、图示对称三相电路中,R=69,Z=(1+j4)9,线电压为 380V,求负载的线电流、相电流和负载R吸收的平均功率。 (7分) Z R 29 3 R 设UAN=220∠0° B R R U AN 220∠0° C— AN =44∠53.13 Z+R 3+j4 Z R l=144 P=312R=3×()2×6=11616 R C P=3,R=3×442×2=11616S=31z=116165、图示对称三相电路中,R=6Ω,Z=(1+j4)Ω,线电压为 380V,求负载的线电流、相电流和负载R吸收的平均功率。 (7分) Z Z Z R R R A B C Z Z Z N R’ A B C R’ R’ = = 2 3 R R = • 设U AN 220 0 = + = + = • • 44 53.13 3 4 220 0 Z R j U I AN AN 3 44 3 = = l P I I ) 6 11616 3 44 3 3 ( 2 2 P = I P R = = 3 3 44 2 11616 2 P = Il R = = 3 11616 2 S = Il Z =