Patent ID: 9519016
Filing Date: 2016-12-13
CPC Classification: G01R

Claim Text:
1. A ground fault detection apparatus detecting a ground fault in an ungrounded AC circuit in which a single-phase three-wire AC power source is connected to a load via a first phase wire, a neutral wire, and a second phase wire, comprising: a first resistive element, a second resistive element, and a third resistive element, one terminal of the first resistive element being connected to the first phase wire, one terminal of the second resistive element being connected to the neutral wire, one terminal of the third resistive element being connected to the second phase wire, the other terminal of the first resistive element, the other terminal of the second resistive element, and the other terminal of the third resistive element being connected to each other via a node, the first resistive element and the second resistive element having an identical resistance value; and a first switching element and a second switching element which are turned on alternately, the first switching element being connected in series with the first resistive element between the first phase wire and the node, and the second switching element being connected in series with the third resistive element between the second phase wire and the node; a current detector detecting a value of a current flowing between the node and a ground point, wherein, in a case where the value detected by the current detector exceeds a predetermined threshold value, the ground fault detection apparatus determines that the ground fault occurs.