Patents by Inventor Normann Fischer
Normann Fischer 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).
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Publication number: 20250147123Abstract: The present disclosure relates to systems and methods to detect a fault in an electric power system. One embodiment may detect a single phase broken conductor in a multi-phase electric power system. An intelligent electronic device (IED) may receive a plurality of measurements over time of a current through an electrical conductor in the electric power system. Based on the measurements of the current, a fault detection subsystem may determine a zero-sequence current, a negative-sequence current, and a positive-sequence current. The fault detection subsystem may determine a ratio of the zero-sequence current, the negative-sequence current, and the positive-sequence current, and may monitor the ratio over time. The fault detection subsystem may identify the broken conductor condition based on the ratio and a fault detection region. A protective action subsystem may implement a protective action based on identification of the broken conductor condition.Type: ApplicationFiled: November 7, 2023Publication date: May 8, 2025Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Yanfeng Gong, Normann Fischer, Gandhali P. Juvekar, Kanchanrao Gangadhar Dase
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Publication number: 20250132599Abstract: The present application relates to generating adaptive protective relay event reports. In one embodiment, a system comprises a power system response subsystem to monitor electrical parameters in an electric power system and to receive a trigger signal from a trigger source based on identification of an event in an electric power system. An adaptive event report subsystem is configured to generate an adaptive report depending on the trigger related to the event and based on a pre-trigger start, a duration, and a sampling rate. The adaptive event report comprises at least one electrical parameter related to the event beginning at a time established by the pre-trigger start, covering an interval established by the duration, and recorded at the sampling rate.Type: ApplicationFiled: October 19, 2023Publication date: April 24, 2025Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Normann Fischer, Douglas I. Taylor, Ritwik Chowdhury
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Patent number: 12249948Abstract: The present disclosure pertains to devices, systems, and methods for monitoring a generator. In one embodiment, the system may include a measurement subsystem to receive a plurality of split-phase measurements of branch currents associated with the at least one generator. A split-phase transverse differential monitoring subsystem may receive the plurality of split-phase measurements of branch currents associated with the at least one generator and may generate an offset value representing a standing split-phase current. A protective action subsystem may generate a first protective action based on the phasor operating current.Type: GrantFiled: August 30, 2022Date of Patent: March 11, 2025Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Matchyaraju Alla, Normann Fischer, Dale S. Finney
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Patent number: 12176716Abstract: The present application discloses systems and methods related to protection of a reactor in an alternating current (AC) electric power system. In one embodiment, a system may include a protective action subsystem to implement a protective action based on identification of a fault condition associated with a reactor. A frequency determination subsystem may determine when a frequency of the AC voltage is outside of a range defined by a lower threshold and an upper threshold and may identify a change in the frequency associated with de-energization of a line in electrical communication with the reactor. A supervisory subsystem may restrain implementation of the protective action when the frequency is outside of the range or when the change in the frequency is associated with de-energization of the line in electrical communication with the reactor.Type: GrantFiled: September 1, 2023Date of Patent: December 24, 2024Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Douglas I. Taylor, Normann Fischer
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Publication number: 20240250518Abstract: A system for high-impedance differential protection for power systems using a variety of signals from the power system. A fault may be detected using filtered phase current or filtered phase voltage magnitudes from current transformers (CTs) connected in parallel by phase. A fault may be detected using filtered phase voltages and raw phase voltages from the CTs. A fault may be detected using raw phase currents and raw phase voltages from the CTs. A fault may be detected using filtered phase currents and raw phase currents. A fault may be detected using raw phase currents and raw neutral currents. The embodiments herein maintain dependability and security of a differential element even when low-class CTs are used. The embodiments herein may allow users to optimize pickup settings even when low-class CTs are used.Type: ApplicationFiled: January 22, 2024Publication date: July 25, 2024Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Normann Fischer, Anushka M. Dissanayake, Jay Hartshorn, Marcos A. Donolo
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Publication number: 20240097449Abstract: The present application discloses systems and methods related to protection of a reactor in an alternating current (AC) electric power system. In one embodiment, a system may include a protective action subsystem to implement a protective action based on identification of a fault condition associated with a reactor. A frequency determination subsystem may determine when a frequency of the AC voltage is outside of a range defined by a lower threshold and an upper threshold and may identify a change in the frequency associated with de-energization of a line in electrical communication with the reactor. A supervisory subsystem may restrain implementation of the protective action when the frequency is outside of the range or when the change in the frequency is associated with de-energization of the line in electrical communication with the reactor.Type: ApplicationFiled: September 1, 2023Publication date: March 21, 2024Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Douglas I. Taylor, Normann Fischer
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Publication number: 20240072697Abstract: The present disclosure pertains to devices, systems, and methods for monitoring a generator. In one embodiment, the system may include a measurement subsystem to receive a plurality of split-phase measurements of branch currents associated with the at least one generator. A split-phase transverse differential monitoring subsystem may receive the plurality of split-phase measurements of branch currents associated with the at least one generator and may generate an offset value representing a standing split-phase current. A protective action subsystem may generate a first protective action based on the phasor operating current.Type: ApplicationFiled: August 30, 2022Publication date: February 29, 2024Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Matchyaraju Alla, Normann Fischer, Dale S. Finney
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Publication number: 20240022112Abstract: Breaker control units (BCUs) may include an output to selectively cause a circuit breaker (CB) to open and close a circuit, a voltage input to monitor a voltage of at least one of a bus and a line, a processor to calculate a point-on-wave switching time, and a remote input configured to be coupled to a remote intelligent electronic device (IED) to receive commands to selectively open and close the CB at a specified optimal time. Electric power systems may include such BCUs. Methods of switching CBs may include monitoring at least one of a bus and a line with a BCU and controlling switching of the CB at a predetermined point-on-wave value with onboard electronics of the BCU. The methods may additionally include calculating a trapped charge and/or a residual flux with an IED and causing the BCU to switch the CB at a specific optimum point-on-wave value.Type: ApplicationFiled: July 12, 2022Publication date: January 18, 2024Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Dale S. Finney, Normann Fischer
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Patent number: 11631972Abstract: The present disclosure relates to systems and methods for protecting against and mitigating the effects of over-excitation of elements in electric power systems. In one embodiment, a system consistent with the present disclosure may comprise a point pair subsystem to receive a plurality of point pairs that define an over-excitation curve for a piece of monitored equipment. The system may receive a plurality of measurements corresponding to electrical conditions associated with the piece of monitored equipment. A logarithmic interpolation subsystem may determine a logarithmic interpolation corresponding to one of the plurality of measurements based on the plurality of point pairs. An over-excitation detection subsystem may detect an over-excitation condition based on the logarithmic interpolation, and a protective action subsystem may implement a protective action based on the over-excitation condition.Type: GrantFiled: December 16, 2020Date of Patent: April 18, 2023Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Dale S. Finney, Normann Fischer, Matchyaraju Alla
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Patent number: 11411390Abstract: Detection of, and protection against faults within a restricted earth fault (REF) zone of a transformer or a generator is disclosed herein. Security of the REF protection element uses comparison of a negative-sequence reference quantity. The REF condition is only detected when there is sufficient ground involvement and a fault in the reverse detection has not been detected. Dependability of the REF protection element in low-impedance grounded systems is improved by ensuring that the element operates when a zero-sequence reference quantity and a neutral operate quantity are orthogonal to each other. The REF protection element further determines an open CT condition and blocks detection of an REF fault upon determination of the open CT condition. A tripping subsystem may issue a trip command based upon detection of the REF condition.Type: GrantFiled: December 31, 2020Date of Patent: August 9, 2022Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Matchyaraju Alla, Satish Samineni, Normann Fischer, Dale S. Finney
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Publication number: 20220209525Abstract: Detection of, and protection against faults within a restricted earth fault (REF) zone of a transformer or a generator is disclosed herein. Security of the REF protection element uses comparison of a negative-sequence reference quantity. The REF condition is only detected when there is sufficient ground involvement and a fault in the reverse detection has not been detected. Dependability of the REF protection element in low-impedance grounded systems is improved by ensuring that the element operates when a zero-sequence reference quantity and a neutral operate quantity are orthogonal to each other. The REF protection element further determines an open CT condition and blocks detection of an REF fault upon determination of the open CT condition. A tripping subsystem may issue a trip command based upon detection of the REF condition.Type: ApplicationFiled: December 31, 2020Publication date: June 30, 2022Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Matchyaraju Alla, Satish Samineni, Normann Fischer, Dale S. Finney
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Publication number: 20220190581Abstract: The present disclosure relates to systems and methods for protecting against and mitigating the effects of over-excitation of elements in electric power systems. In one embodiment, a system consistent with the present disclosure may comprise a point pair subsystem to receive a plurality of point pairs that define an over-excitation curve for a piece of monitored equipment. The system may receive a plurality of measurements corresponding to electrical conditions associated with the piece of monitored equipment. A logarithmic interpolation subsystem may determine a logarithmic interpolation corresponding to one of the plurality of measurements based on the plurality of point pairs. An over-excitation detection subsystem may detect an over-excitation condition based on the logarithmic interpolation, and a protective action subsystem may implement a protective action based on the over-excitation condition.Type: ApplicationFiled: December 16, 2020Publication date: June 16, 2022Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Dale S. Finney, Normann Fischer, Matchyaraju Alla
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Patent number: 11316455Abstract: Detection and protection against electric power generator rotor turn-to-turn faults, rotor multi-point-to-ground faults, and rotor permanent magnet faults is provided herein. A fractional harmonic signal is used to determine the rotor fault condition. The fractional harmonic signal may be a fractional harmonic magnitude of the circulating current of one phase. The fractional harmonic may be a fractional harmonic magnitude of a neutral voltage. A tripping subsystem may issue a trip command based upon detection of a rotor turn-to-turn fault condition.Type: GrantFiled: August 26, 2020Date of Patent: April 26, 2022Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Matchyaraju Alla, Ritwik Chowdhury, Normann Fischer, Dale S. Finney, Rogerio Scharlach
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Patent number: 11196369Abstract: Protection devices prevent damage to synchronous generators during loss-of-field events. In various embodiments, a first protective element is associated with a first protection zone to protect a generator from a loss-of-field event at full load. A second protective element is associated with a second protection zone to prevent thermal overload during underexcited operation of the generator and to protect from loss-of-filed at light load. A third protective element associated with a third protection zone limits operation of the generator within the generator's specific steady-state stability limits. A fourth protective element is associated with a fourth protection zone to provide an alarm prior to operation of the second protective element.Type: GrantFiled: May 29, 2019Date of Patent: December 7, 2021Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Matchyaraju Alla, Armando Guzman-Casillas, Dale S. Finney, Normann Fischer
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Patent number: 11143715Abstract: Disclosed herein are systems for determining a broken conductor condition in a multiple-phase electric power delivery system. It has been observed that broken conductors pose a safety concern when occurring in the presence of people or vulnerable environmental conditions. Broken conductor conditions disclosed herein may be used to detect and trip the phase with the broken conductor, thus reducing or even eliminating the safety risk. Further, a distance to the opening may be determined.Type: GrantFiled: August 14, 2020Date of Patent: October 12, 2021Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Jordan Bell, Kanchanrao Gangadhar Dase, Sajal Harmukh, Normann Fischer, Daqing Hou
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Publication number: 20210109147Abstract: The present disclosure pertains to systems and methods for monitoring and protecting an electric power system. In one embodiment, a system may comprise line-mounted wireless current transformers to measure at least one parameter of an alternating current (AC), receive a synchronization signal at which to measure the AC, and send a message comprising the measured AC. The system may also comprise an intelligent electronic device (IED) to send the synchronization signal to and receive the messages from the line-mount wireless current transformers, determine whether a high-impedance fault (HiZ) exists between the line-mounted wireless current transformers, and implement a control action based on the existence of the HiZ fault.Type: ApplicationFiled: November 19, 2019Publication date: April 15, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Normann Fischer, Raymond W. Rice, Ravindra P. Mulpuri, James Mobley
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Patent number: 10962608Abstract: The present disclosure pertains to systems and methods for monitoring and protecting an electric power system. In one embodiment, a system may comprise line-mounted wireless current transformers to measure at least one parameter of an alternating current (AC), receive a synchronization signal at which to measure the AC, and send a message comprising the measured AC. The system may also comprise an intelligent electronic device (IED) to send the synchronization signal to and receive the messages from the line-mount wireless current transformers, determine whether a high-impedance fault (HiZ) exists between the line-mounted wireless current transformers, and implement a control action based on the existence of the HiZ fault.Type: GrantFiled: November 19, 2019Date of Patent: March 30, 2021Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Normann Fischer, Raymond W. Rice, Ravindra P. Mulpuri, James Mobley
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Publication number: 20210067072Abstract: Detection and protection against electric power generator rotor turn-to-turn faults, rotor multi-point-to-ground faults, and rotor permanent magnet faults is provided herein. A fractional harmonic signal is used to determine the rotor fault condition. The fractional harmonic signal may be a fractional harmonic magnitude of the circulating current of one phase. The fractional harmonic may be a fractional harmonic magnitude of a neutral voltage. A tripping subsystem may issue a trip command based upon detection of a rotor turn-to-turn fault condition.Type: ApplicationFiled: August 26, 2020Publication date: March 4, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Matchyaraju Alla, Ritwik Chowdhury, Normann Fischer, Dale S. Finney, Rogerio Scharlach
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Publication number: 20210048486Abstract: Disclosed herein are systems for determining a broken conductor condition in a multiple-phase electric power delivery system. It has been observed that broken conductors pose a safety concern when occurring in the presence of people or vulnerable environmental conditions. Broken conductor conditions disclosed herein may be used to detect and trip the phase with the broken conductor, thus reducing or even eliminating the safety risk. Further, a distance to the opening may be determined.Type: ApplicationFiled: August 14, 2020Publication date: February 18, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Jordan Bell, Kanchanrao Gangadhar Dase, Sajal Harmukh, Normann Fischer, Daqing Hou
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Patent number: 10819261Abstract: Electric power generator protection is secured by detecting wiring errors to an intelligent electronic device using terminal third voltages at the terminal (VT3) and third harmonic voltages at the neutral (VN3). When an angle between VT3 and VN3 is outside of an acceptable range, a wiring defect is detected, and certain protective operations are blocked. An alarm may be generated, facilitating personnel to identify and rectify the wiring defect. Wiring defects may further be detected when a torque calculated using VT3 and VN3 exceeds a predetermined error threshold. Security of protection elements is increased by detection of wiring defects that may have resulted in misoperation of the protection elements.Type: GrantFiled: January 2, 2020Date of Patent: October 27, 2020Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Ritwik Chowdhury, Dale S. Finney, Normann Fischer