Patents by Inventor Wasif Ahmad

Wasif Ahmad has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Systems and methods for improving restricted earth fault protection
    Patent number: 11177645
    Abstract: A transformer system including a transformer including a set of wye windings, a three-phase current transformer, a neutral-current transformer, and a controller. The three-phase current transformer outputs a first signal indicative of a three-phase current conducting through the set of wye windings and the three-phase current transformer. The neutral-current transformer couples the current flowing from the ground to the neutral node of the transformer, and outputs a second signal indicative of a neutral current conducting from the ground node to the neutral node of the transformer. The controller receives the first signal and the second signal, determines whether an external ground fault condition or an internal ground fault condition is present based on the three-phase current and the neutral current, and determines whether a wiring error is present for the three-phase current transformer or the neutral-current transformer based on the three-phase current and the neutral current.
    Type: Grant
    Filed: November 22, 2019
    Date of Patent: November 16, 2021
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Ritwik Chowdhury, Matchyaraju Alla, Vinod K. Yedidi, Jakov Vico, Wasif Ahmad
  • SYSTEMS AND METHODS FOR IMPROVING RESTRICTED EARTH FAULT PROTECTION
    Publication number: 20210159691
    Abstract: A transformer system including a transformer including a set of wye windings, a three-phase current transformer, a neutral-current transformer, and a controller. The three-phase current transformer outputs a first signal indicative of a three-phase current conducting through the set of wye windings and the three-phase current transformer. The neutral-current transformer couples the current flowing from the ground to the neutral node of the transformer, and outputs a second signal indicative of a neutral current conducting from the ground node to the neutral node of the transformer. The controller receives the first signal and the second signal, determines whether an external ground fault condition or an internal ground fault condition is present based on the three-phase current and the neutral current, and determines whether a wiring error is present for the three-phase current transformer or the neutral-current transformer based on the three-phase current and the neutral current.
    Type: Application
    Filed: November 22, 2019
    Publication date: May 27, 2021
    Applicant: Schweitzer Engineering Laboratories, Inc.
    Inventors: Ritwik Chowdhury, Matchyaraju Alla, Vinod K. Yedidi, Jakov Vico, Wasif Ahmad