Problem $3.(20$ points$)$

Two synchronous machines are connected through three$-$phase transformers to the transmission line. The ratings and reactances of the machines and transformers are: Machines $1$ and $2$: $100$MVA,$20kV,x_1=x_2=20\%,x_0=6\%,x_n=3\%.$

Transformers T$1$ and T$2$: $100$MVA,$20\frac{}{345}YkV,x=6\%.$

$1$

The transmission line has the following parameters: $100$MVA,$345kV,x_1=x_2=15\%,x_0=40\%$

Draw the zero sequence network of the system. You do not need to draw the positivesequence and negative$-$sequence networks.