RECORDING DEVICE FOR DOUBLE GROUND FAULTS IN ISOLATED NEUTRAL NETWORKS Russian patent published in 2018 - IPC H02H3/16 

FIELD: electricity.

SUBSTANCE: device contains a power source, a three-phase power network with current transformers in two phases connected to the consumers via power lines and with a voltage transformer, one of whose windings is connected to an open delta and connected through a rectifying bridge to the first reactive member, the second reacting member, connected by an output to the second input of the AND element, and the output of the AND element is connected to the output member, characterized in that the output of the first reacting member is connected to the first memory element and the first input of the AND element through the delay element of the disappearance of the output signal, and the second reacting member is connected to the output of the negative sequence current filter connected to the secondary windings of the current transformers, the third of which is installed in the third phase of the power network, the output member being connected to the second memory element.

EFFECT: ensuring the identification of a double ground fault.

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