Monitor device, ground fault protection circuit and techniques
AssigneeLittelfuse, Inc.
InventorsKristophor Jensen, Kip M. Larson, Cornelis Verhey
Life of this patent
Estimating the term…
Abstract
A neutral grounding resistor fault protection arrangement. The fault protection arrangement may include a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end; a sense circuit, coupled to the non-ground end of the neutral grounding resistor; and a neutral grounding monitor, coupled to the non-ground end of the neutral grounding resistor, the neutral grounding monitor comprising an injection signal generator, the injection signal generator arranged to generate a frequency of 240 Hz or greater.
Claims16
A fault protection arrangement, comprising:
- a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end;
- a neutral grounding resistance monitor assembly, comprising:
- a sense circuit, coupled to the non-ground end of the neutral grounding resistor;
- and
- an injection signal generator, coupled to the non-ground end of the neutral grounding resistor the injection signal generator arranged to generate a frequency of 240 Hz or greater;
- and
- a capacitor, having a first electrode coupled to receive a signal from the injection signal generator, and a second electrode, coupled to the non-ground end of the neutral grounding resistor, wherein the capacitor comprises:
- a printed circuit board body;
- a first conductive trace, disposed on a first surface of the printed circuit board body, and covering a majority of the first surface;
- and
- a second conductive trace, disposed one a second surface of the printed circuit board body, and covering a majority of the second surface, opposite the first surface.
A neutral grounding resistor monitor assembly, comprising:
- a sense resistor circuit, having an output, arranged to connect to a non-ground end of a neutral grounding resistor;
- an injection signal generator, arranged to connect to the non-ground end of the neutral grounding resistor the injection signal generator arranged to generate an alternating current signal;
- and
- an injection capacitor, the injection capacitor comprising a first electrode coupled to receive a signal from the injection signal generator, and a second electrode, arranged to connect to the non-ground end of the neutral grounding resistor, wherein the injection capacitor comprises:
- a printed circuit board body;
- a first conductive trace, disposed on a first surface of the printed circuit board body, and covering a majority of the first surface;
- and
- a second conductive trace, disposed one a second surface of the printed circuit board body, and covering a majority of the second surface, opposite the first surface.
A fault protection method, comprising:
- connecting a power system to a fault protection arrangement, the fault protection arrangement comprising:
- a neutral grounding resistor, the neutral grounding resistor comprising a ground end and a non-ground end;
- and
- a neutral grounding resistor monitor assembly, comprising:
- a sense circuit, coupled to the non-ground end of the neutral grounding resistor, the sense circuit comprising a sense resistor, and an injection capacitor;
- and
- an injection signal generator, coupled to the non-ground end of the neutral grounding resistor;
- and
- probing a resistance of the neutral grounding resistor by sending an injection signal from the sense circuit;
- wherein a frequency of the injection signal ranges from 240 Hz to 10 MHz, and wherein an edge rate of the injection signal ranges from 240 Hz to 10 GHz.
Dependencies are inferred from the claim text.