Insulation fault location systems and methods for insulation fault location for a redundant DC power supply system coupled to diodes

An insulation fault location system for an ungrounded DC power supply system, which is redundantly fed from a first Direct voltage supply source coupled to diodes and a second Direct voltage supply source coupled to diodes and to which a consumer is redundantly coupled via a first supply line consisting of two active conductors and a second supply line consisting of two active conductors, the insulation fault location system comprising a setting device for increasing a supply voltage of the first or the second Direct voltage supply source, a test current generator for supplying a test current and an insulation fault location device, to which a first measuring current transformer for capturing a first test current portion flowing in the first supply line and a second measuring current transformer for capturing a second test current portion flowing in the second supply line are coupled,

• wherein a current path having a current setting device is arranged between the active conductors of the first supply line and between the active conductors of the second supply line, respectively, said current setting device setting a compensating current dependent on load current, said compensating current being equal to an interfering DC differential current (Idcdiff,a, Idcdiff,b) in the respective supply line caused by increasing the supply voltage and being captured on the primary side in the opposite direction of the interfering DC differential current by the respective measuring current transformer.

A method for insulation fault location in an ungrounded DC power supply system, which is redundantly fed from a first Direct voltage supply source coupled to diodes and a second Direct voltage supply source coupled to diodes and to which a consumer is redundantly coupled via a first supply line consisting of two active conductors and a second supply line consisting of two active conductors, the method comprising steps:

• increasing a supply voltage of the first Direct voltage supply source or the second Direct voltage supply source using a setting device,
• supplying a test current using a test current generator
• capturing a first test current portion flowing in the first supply line using a measuring current transformer coupled to an insulation fault location device, and capturing a second test current portion flowing in the second supply line using a second measuring current transformer coupled to the insulation fault location device,
• wherein generating a first compensating current driven by Direct voltage supply sources in a first resistance path between the active conductors of the first supply line, and generating a second compensating current driven by the Direct voltage supply sources in a second resistance path between the active conductors the supply line (8b), the respective compensating current being equal to an interfering DC differential current in the respective supply line caused by increasing the supply voltage and being captured on the primary side in the opposite direction of the interfering DC differential current by the respective measuring current transformer.

A method for insulation fault location in an ungrounded DC power supply system, which is redundantly fed from a first Direct voltage supply source coupled to diodes and a second Direct voltage supply source coupled to diodes and to which a consumer is redundantly coupled via a first supply line consisting of two active conductors and a second supply line consisting of two active conductors, the method comprising performance steps:

• increasing a supply voltage of the first Direct voltage supply source or the second Direct voltage supply source using a setting device,
• supplying a test current using a test current generator
• capturing a first test current portion flowing in the first supply line using a first measuring current transformer coupled to an insulation fault location device, and capturing a second test current portion flowing in the second supply line using a second measuring current transformer coupled to the insulation fault location device apparatus,
• characterized by
• generating and setting a compensating current dependent on load current in a current path between the active conductors of the first supply line and between the active conductors of the second supply line, respectively, by means of current setting device (34a, 34b), the respective compensating current being equal to an interfering DC differential current in the respective supply line caused by increasing the supply voltage and being captured on the primary side in the opposite direction of the interfering DC differential current by the respective measuring current transformer.