FAULT DETECTING APPARATUS FOR AC FILTER CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a fault detecting apparatus for easily and inexpensively detecting a decrease in an electrostatic capacity of a capacitor, during an operation of a power converter including a shunt-connected capacitor as an AC filter at an output side. ;SOLUTION: A fault detecting apparatus for an AC filter circuit comprises a zero-phase current transformer 7 penetrating three connecting wires to a three-phase capacitor 5A, a phase current detector 8 for detecting a current flowing any one of the three wires, first and second low pass filters 9, 10 respectively connected to output sides of the transformer 7 and the detector 8, and discriminators 11, 12, 13 for discriminating a capacity decrease of the capacitor when an output of the filter 9 becomes a predetermined value or more or an output of the filter 10 becomes a predetermined value or less.;COPYRIGHT: (C)1999,JPO