SELECTIVE ELECTRONIC TRIPPING ELEMENT

摘要

The threshold (S) for instantaneous triggering of the selective tripping element is a decreasing function of a variable (tc) that is representative of the time required for the current to reach a peak level. The variation curve S(tc) is disposed between the first and second curves that are obtained experimentally and represent the peak level envelopes of the current. The first curve is obtained when the circuit breaker that is associated with the selective tripping element is insulated and the second curve is obtained when it is series connected to another downstream circuit breaker.