When a fault occurs inside the busbar zone, such as a short circuit to ground, a portion of the incoming current is diverted through the fault path. This diversion upsets the current balance, as current flows into the bus but does not leave via the intended feeders. During high magnitude faults a CT saturation detector additionally supervises the differential protection. Common copper busbar faults primarily stem from electrical and mechanical stresses, often leading to reduced performance or system failure. A single test of the percentage restraint characteristic, does not provide enough confidence for the correct. If a fault occurs on a busbars, considerable damage and disruption of supply will occur unless some form of quick-acting automatic protection is provided to isolate the faulty busbar. The busbar zone, for the purpose of protection, includes not only the bus bars themselves but also the isolating. A busbar protection must be capable of clearing all phase-to-earth faults, and in the case where they can occur, phase-to-phase faults. Due to the fact that the short-circuit levels of bus bars.
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