Alternating current limiting type semiconductor current circuit breaker.

摘要

An alternating current limiting type semiconductor current circuit breaker for a transmission or distribution line system comprises: a first circuit formed of a transformer or reactor (1) and a capacitor or capacitors (2, 20) which provide a series resonant circuit during steady-state operation of the line system, a second circuit connected in series with the secondary winding side of the transformer and formed by a resistor (4) and a nonlinear resistance element (30), a third circuit connected in parallel with said first circuit and formed by a series connection of a reactor (5) and resistor (6), and a semiconductor switchin device (7) connected in series with the parallel connection of said first and third circuits. The nonlinear solid-state resistance element (30) is a zinc oxide nonlinear type resistance element the resistance of which is lowered upon occurrence of an earth fault or the like to provide for an increase in the combined impedance of the parallel connection of said first and third circuits for limiting the overcurrent flowing through the current circuit breaker.