(a) An 11 KV, 500 MVA circuit breaker suddenly closes on to a fault.…

Question

(a) An 11 KV, 500 MVA circuit breaker suddenly closes on to a fault. Determine (i) the symmetrical breaking current (ii) the asymmetrical breaking current assuming 50% dc component (iii) the peak making current (iv) the short-time current rating.

(b) Explain the construction of $\text{SF}_6$ breaker with diagram.