Patent ID: 8311785

Claim:
In a ground fault detection device comprising a transformer having a primary coil couplable to a power-line conductor and a secondary coil coupled to a detection circuit, the detection circuit comprising: a non-transitory computer readable medium containing computer readable instructions stored therein for causing a processor to: couple a secondary coil of the transformer to a first impedance converting circuit having a first pair of transconductance circuits and a first capacitor; couple a second impedance converting circuit having a second pair of transconductance circuits and a second capacitor in parallel with the first capacitor, wherein the second impedance converting circuit converts the second capacitor into an inductor in parallel with the first capacitor; convert, in the first impedance converting circuit, the parallel inductor and capacitor into a series connected inductance and capacitance, wherein the inductor becomes the capacitance and the capacitor becomes the inductance; and measure an output of the first impedance converting circuit to detect a ground fault; and couple a detector to the output of the first impedance converting circuit to detect a ground fault, wherein the detection circuit receives a signal containing current information and the detector measures the current as a voltage.