In underground applications, a fault indicator is placed at cable terminations along each primary cable. The indicators upstream of the fault will trip, and the indicators downstream of the fault will remain in the nontripped position. As a result, the service team can easily identify the faulted section of cable or equipment without going through a time consuming isolation process. Underground applications can include transformers, switchgear, cabinets, junction boxes, and splices.
In overhead applications, the easy to spot displays on fault indicators lead the line crew to the problem section of line. Overhead applications can include unfused taps, long feeders with midline reclosers, sectioning switchgear, transitions, and feeders.
Two of the biggest challenges associated with existing fault indicators are 1) they can be expensive to purchase in volume and 2) they require recurring maintenance in order to keep functioning properly. Cumulative purchase cost and recurring maintenance are two primary reasons why utility companies with limited budgets and resources are unable to deploy more fault indicators within their vast power infrastructure.