Problem $2.(30$ points total$)$

Figure $2$ shows two typical bus arrangements $($ring bus arrangement and double$-$breaker double bus arrangement$).$ For each arrangement: $($a$)$ Draw the protective zones; $($b$)$ Identify the breakers that open under primary protection for a fault on Line $1.($c$)$ Identify the breakers that open under primary protection for a bus fault at P$1.$

$($a$)$ Ring bus

Bus $1$

$P_1$

$($b$)$ Double$-$breaker double bus

Figure $2$: Systems for Problem $2$