| 摘要 |
PURPOSE: To prevent a to-be-protected device from being triggered at saturation of a current converter, by generating a protective trigger signal when a differential current is larger than the first limit value and besides when the suppressive current to suppress a protective trigger signal is smaller than the second limit value. CONSTITUTION: In the case that AC current In >2IN as against nominal current IN, protective trigger is performed. Then, in case that current converters 3, 8, and 18 are not equal in saturation and ins case of external short circuit 10, the suppressive current IH is enlarged as desired. Usually, IH>IN. Moreover, the fear of the function drop caused by the components of the load current flowing in the substances 4-6 and 17 for protection is avoided by so arranging the trigger as to be performed in case of small AC current on side and besides concurrently in the case of large real number section components. |
