DC ground fault detection device and ground fault circuit determination device

摘要

PROBLEM TO BE SOLVED: To determine a direct current circuit with a ground fault, among multiple direct current circuits.SOLUTION: A direct current earth detector comprises: first and second terminals that are connected to one and the other bus lines of a first direct-current power source, respectively; first and second voltage detection elements that are connected between the first and second terminals in series; a third terminal for connecting a connection point between the first and second voltage detection elements to a ground; fourth and fifth terminals that are connected to one and the other bus lines of a second direct-current power source, respectively; capacitors for capacitively coupling the first and fourth terminals; contact points for opening and closing cable runs between the second and fifth terminals; an earth determination section that determines whether or not a ground fault occurs at first and second direct current circuits, on the basis of at least one of voltage to be detected by the first and second voltage detection elements and current flowing between the connection point and the third terminal; and an earth circuit determination section for, when the earth determination section determines that the ground fault occurs in a closing state of all the contact points, sequentially opening the contact points and determining a direct current circuit with a ground fault on the basis of a determination result of the earth determination section in each opening and closing state of the contact points.