Emprimus, LLC

Techhold, LLC

Terry Lee Volkmann

Greg Fuchs

David Blake Jackson

Frederick R Faxvog

Wallace Jensen

Gale K Nordling

George E Anderson

James Nicholas Ruehl

Brian Groh

Methods and systems for ensuring operation of one or more circuit breakers electrically connected on a phase of a multi-phase power line on a transformer electrically connected within a power grid at a substation are disclosed. The method includes detecting, at the transformer, a direct current component of a multi-phase power signal received at the transformer, the direct current component comprising a direct current received at a transformer neutral, the transformer neutral being electrically connected to a ground. The method further includes determining whether the direct current is above a predetermined threshold, the predetermined threshold being based on a determination that, above the predetermined threshold, at least one of the one or more circuit breakers is incapable of reliable operation. The method includes, in response to a determination that the direct current component is above the predetermined threshold, blocking the direct current between the transformer neutral and a ground.

Method and system for improved operation of power grid components in the presence of direct current (DC)

A continuous grounding system for use in an alternating current system including a transformer is disclosed. The system includes a switch assembly connected between a transformer neutral of a transformer and a ground, the switch assembly having an open position and a closed position, the open position disrupting the path through the switch assembly between the electrical connection and the transformer neutral, and the closed position establishing a path connecting the electrical connection to the transformer neutral through the switch assembly, wherein in normal operation of the alternating current electrical device the switch assembly remains in a closed position. The system also includes a DC blocking component positioned in parallel with the switch assembly and connected between the transformer neutral and the ground. The system further includes a control circuit configured to control the switch assembly, the control circuit including a sensor configured to actuate the switch assembly to an open position upon detection of a predetermined harmonic signal threshold at one of the transformer phases or a predetermined threshold of DC current between the transformer neutral and ground.

Continuous uninterruptable AC grounding system for power system protection

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St. Michael, MN, United States of America

Terry Lee Volkmann