Patents by Inventor Kei Hao
Kei Hao 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: 20210231723Abstract: Line-mounted devices for determining fault magnitude in an electric power delivery system even under current-transformer (CT) saturation are disclosed herein. Fault magnitude is calculated using unsaturated regions of a current waveform captured by the line-mounted device. The method of determining the unsaturated regions is computationally efficient. Fictitious peaks are removed, and the unsaturated regions are determined based on fractions of the valid peaks. Fault current magnitude is calculated using sample values in the unsaturated regions.Type: ApplicationFiled: January 23, 2020Publication date: July 29, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20210231736Abstract: Systems and methods to detect that a protective device is operating outside of a time inverse overcurrent tolerance region are described. For example, a central monitoring station may obtain a time inverse overcurrent tolerance region of a protective device on a power line. The central monitoring station may obtain a fault magnitude measurement and a fault duration measurement of a wireless line sensor on the power line. The central monitoring station may determine that the protective device is operating outside of the tolerance region based at least in part on the fault magnitude measurement and the fault duration measurement. The central monitoring station may provide a signal indicating that there is a potential issue with the protective device.Type: ApplicationFiled: January 24, 2020Publication date: July 29, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Shankar V. Achanta, Kei Hao
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Patent number: 11075519Abstract: Systems and methods to control a capacitor bank based on the power flow direction are described herein. For example, a capacitor bank controller (CBC) may determine a power flow direction based on one or more current measurements and one or more voltage measurements. The CBC may control the capacitor bank using a first quantity when the power flow direction is in a first direction. The CBC may control the capacitor bank using a second quantity when the power flow direction is in a second direction. The second quantity may be different from the first quantity to account for the relationship between sensors of the CBC with respect to the capacitor bank on the power line.Type: GrantFiled: October 30, 2019Date of Patent: July 27, 2021Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Kei Hao, Jeremy William Blair
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Publication number: 20210109558Abstract: Systems and methods to control a capacitor bank based on the power flow direction are described herein. For example, a capacitor bank controller (CBC) may determine a power flow direction based on one or more current measurements and one or more voltage measurements. The CBC may control the capacitor bank using a first quantity when the power flow direction is in a first direction. The CBC may control the capacitor bank using a second quantity when the power flow direction is in a second direction. The second quantity may be different from the first quantity to account for the relationship between sensors of the CBC with respect to the capacitor bank on the power line.Type: ApplicationFiled: October 30, 2019Publication date: April 15, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Kei Hao, Jeremy William Blair
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Publication number: 20210109137Abstract: Systems and methods for calculating load direction even under adverse environmental conditions are provided. A system may include sensing circuitry and processing circuitry. The sensing circuitry may sense a first parameter and a second parameter of the electrical waveform on the transmission line of the electric power distribution system. The processing circuitry may determine a present load direction of an electrical waveform using a first method based at least in part on the first parameter in response to detecting that the sensing circuitry is experiencing a first environmental condition. The processing circuitry may determine the present load direction of the electrical waveform using a second method based at least in part on the second parameter and not the first parameter in response to detecting that the sensing circuitry is experiencing a second environmental condition.Type: ApplicationFiled: December 26, 2019Publication date: April 15, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20210109136Abstract: An intelligent electronic device (IED) that associates current measurements from wireless current sensors with voltages of a power line are described. For example, an IED may receive a first current measurement from a first WCS on a first phase of a power line. The IED may receive a first voltage quantity from a voltage sensing device on the first phase of the power line. The IED may determine a phase shift between the first voltage quantity and the first current measurement to use as a reference phase shift. The IED may receive a second current measurement from a second WCS on a second phase of the power line. The IED may associate the second WCS with a second voltage quantity based at least in part on the reference phase shift.Type: ApplicationFiled: December 10, 2019Publication date: April 15, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20210109135Abstract: A system is provided for monitoring and protecting an electric power distribution system using intelligent electronic devices that may rely on the communication from wireless electrical measurement devices. A wireless electrical measurement device may obtain electrical measurements on a transmission line and wirelessly transmit messages containing the measurements to an intelligent electronic device. The intelligent electronic device may determine a consistency of wireless communication from the wireless electrical measurement device based at least in part on the received messages. When the wireless communication is determined to be presently consistent, the intelligent electronic device may operate in a first mode. When the wireless communication is determined not to be presently consistent, the intelligent electronic device may operate in a second mode.Type: ApplicationFiled: October 11, 2019Publication date: April 15, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20210109141Abstract: Systems, methods, and devices are provided for controlling part of an electric power distribution system using an intelligent electronic device that may rely on communication from wireless electrical measurement devices. Wireless electrical measurement devices associated with different phases of power on an electric power distribution system may send wireless messages containing electrical measurements for respective phases to an intelligent electronic device. When wireless communication with one of the wireless electrical measurement devices becomes inconsistent or lost, the intelligent electronic device may synthesize the electrical measurements of the missing phase using electrical measurements of remaining phases. The intelligent electronic device may use the synthesized electrical measurements to control part of the electric power distribution system.Type: ApplicationFiled: January 14, 2020Publication date: April 15, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20210102985Abstract: The present disclosure relates to a wireless neutral current sensor (WNCS) for monitoring a neutral cable of a capacitor bank. The WNCS may include a power storage device that provides power to allow the WNCS to send a test signal to a capacitor bank controller (CBC) of the capacitor bank to confirm operation of the WNCS during commissioning. The WNCS may include processing and communication circuitry that, during operation, detects an electrical characteristic on the neutral cable. The processing and communication circuitry may provide a message indicating the electrical characteristic to the CBC.Type: ApplicationFiled: October 3, 2019Publication date: April 8, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Kei Hao, Shankar V. Achanta, Raymond W. Rice
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Publication number: 20210088595Abstract: The present disclosure relates to a capacitor bank controller that automatically determines the size of a capacitor bank. For example, the capacitor bank controller may obtain voltage and current measurements while the capacitor bank is disconnected from the power line. Further, the capacitor bank controller may obtain voltage and current measurements while the capacitor bank is connected to the power line. The capacitor bank controller may determine the size of the capacitor bank based on impedances from the voltage and current measurements while the capacitor bank is connected and disconnected.Type: ApplicationFiled: September 19, 2019Publication date: March 25, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20210088555Abstract: The present disclosure relates to a capacitor bank control system that uses a combination of line post sensors and wireless current sensors for control operations. For example, a capacitor bank controller may include one or more inputs that electrically couple to a line post sensor to allow the capacitor bank controller to obtain line post sensor measurements. The capacitor bank controller may include a transceiver that receives wireless current sensor measurements from first and second wireless current sensors. The capacitor bank controller may include a processor that controls one or more switching devices of a capacitor bank based at least in part on a combination of line post sensor measurements and wireless current sensor measurements.Type: ApplicationFiled: September 24, 2019Publication date: March 25, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20210083478Abstract: The present disclosure relates to controlling a capacitor bank using current measurements from different current sensors depending on the power flow direction. For example, the system may perform capacitor bank control operations using current measurements from a first current sensor coupled to the power line between an initial source and the capacitor bank when power is flowing in a first power flow direction on the power line. The system may determine that power flow on the power line has changed from flowing in the first power flow direction to flowing in a second power flow direction from an updated source, different from the initial source. The system may, upon detecting the change in the power flow direction perform control operations of the capacitor bank using current measurements from a second current sensor between an updated source and the capacitor bank.Type: ApplicationFiled: September 16, 2019Publication date: March 18, 2021Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Kei Hao, Mark W. Feltis, Naresh Malla
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Patent number: 10830832Abstract: The present disclosure relates to directionality of events on line sensors for power lines. In an embodiment, a line sensor may include phase detection circuitry that detects a feature of an operating parameter of a power line prior to an occurrence of an event. The phase detection circuitry may provide a time associated with the feature. The line sensor may include sensor circuitry that sends an activation signal. The line sensor may include a controller that, upon receiving the activation signal, measures samples of the operating parameter. The line sensor may determine a relative direction of the event based on the plurality of times detected prior to the event and the measured samples of the operating parameter.Type: GrantFiled: April 30, 2018Date of Patent: November 10, 2020Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Kei Hao, Naiden K. Spasov, Armando Guzman-Casillas
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Publication number: 20200319240Abstract: Improvements in the functioning of a line-mounted device to calculate a direction to a fault during current transformer (CT) saturation are disclosed herein. The line-mounted device may determine a load direction using voltage and current zero-crossings and a power system frequency before the fault condition. The line-mounted device may determine a fault direction in relation to the direction to the load after calculating and removing direct current (DC) components of a sampled current signal using valid sample pairs obtained during unsaturated regions of peaks of the sampled current signal. The line-mounted device may indicate the direction to the fault. A system of line-mounted devices may be used to determine a faulted section of a power system using indications of fault direction.Type: ApplicationFiled: April 5, 2019Publication date: October 8, 2020Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Patent number: 10637233Abstract: Improvements in the functioning of a line-mounted device to calculate a fault current magnitude during current transformer (CT) saturation are disclosed herein. The line-mounted device may determine direct current (DC) components of a sampled current signal using valid sample pairs obtained during unsaturated regions of peaks of the sampled current signal. The DC components may be removed from the sampled current signal to produce a sinusoidal current signal. The fault current magnitude may be calculated using the sinusoidal current signal with the DC components removed.Type: GrantFiled: June 15, 2018Date of Patent: April 28, 2020Assignee: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20190386485Abstract: Improvements in the functioning of a line-mounted device to calculate a fault current magnitude during current transformer (CT) saturation are disclosed herein. The line-mounted device may determine direct current (DC) components of a sampled current signal using valid sample pairs obtained during unsaturated regions of peaks of the sampled current signal. The DC components may be removed from the sampled current signal to produce a sinusoidal current signal. The fault current magnitude may be calculated using the sinusoidal current signal with the DC components removed.Type: ApplicationFiled: June 15, 2018Publication date: December 19, 2019Applicant: Schweitzer Engineering Laboratories, Inc.Inventor: Kei Hao
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Publication number: 20190331722Abstract: The present disclosure relates to directionality of events on line sensors for power lines. In an embodiment, a line sensor may include phase detection circuitry that detects a feature of an operating parameter of a power line prior to an occurrence of an event. The phase detection circuitry may provide a time associated with the feature. The line sensor may include sensor circuitry that sends an activation signal. The line sensor may include a controller that, upon receiving the activation signal, measures samples of the operating parameter. The line sensor may determine a relative direction of the event based on the plurality of times detected prior to the event and the measured samples of the operating parameter.Type: ApplicationFiled: April 30, 2018Publication date: October 31, 2019Applicant: Schweitzer Engineering Laboratories, Inc.Inventors: Kei Hao, Naiden K. Spasov, Armando Guzman-Casillas