b. Upstream isolation: If there is at least one
switching device between P and C, the one closest
to C will be opened to isolate the faulted
component. Since we assume all switches
including this one, S, is automatic, no sustained
interruption will be experienced at customers
between P and S. Although they will experience
momentary interruptions, this paper addresses the
indices related to sustained interruption (SAIFI
and SAIDI), which are more popularly adopted.