With Phase Sequence Network Analyzer Patents (Class 361/76)
  • Patent number: 10536117
    Abstract: Methods, circuits, and apparatuses that provide Buffer Amplifier, containing Amplifiers and Buffer Drivers, one or more of the following: ultra low power Buffer Amplifier, capable of having high gain, low noise, high speed, near rail-to-rail input-output voltage span, high sink-source current drive capability for an external load, and able to operate at low power supply voltages. Methods, circuits, and apparatuses that provide regulated cascode (RGC) current mirrors (CM) capable of operating at low power supply and having wide input-output voltage spans.
    Type: Grant
    Filed: October 26, 2018
    Date of Patent: January 14, 2020
    Inventor: Ali Tasdighi Far
  • Patent number: 10027111
    Abstract: An auxiliary circuit for providing current to an external device includes a first switch disposed between a first node and a second node. The first switch is configured to electrically couple the first node to the second node when a first voltage exceeds a first threshold. A comparison circuit has an input coupled to the second node and is configured to compare a second voltage at the input to a second threshold. A second switch has a control terminal coupled to an output of the comparison circuit, a first terminal coupled to a source, and a second terminal for coupling to the external device. The comparison circuit is configured to provide a third voltage at control terminal when the second voltage exceeds the second threshold. The second switch is configured to provide the current from the source to the external device when the third voltage exceeds a threshold of the second switch.
    Type: Grant
    Filed: August 24, 2015
    Date of Patent: July 17, 2018
    Assignee: Mitel Networks, Inc.
    Inventor: George Michael Hey
  • Patent number: 9671449
    Abstract: A system for detecting an electrical fault in an electrical installation including several electrical conductors, the system including at least two measurement modules, each measurement module including first radioelectric communication device, a sensor for measuring each electrical magnitude associated with a corresponding electrical conductor and a first clock defined by a first initial instant and a first clock frequency, each measured value being suitable for being associated with a first instant of measurement, determined with respect to the first initial instant and as a function of the first frequency, an acquisition unit, including second radioelectric means adapted for communicating with the first radioelectric communication device.
    Type: Grant
    Filed: July 13, 2015
    Date of Patent: June 6, 2017
    Assignee: SCHNEIDER ELECTRIC INDUSTRIES SAS
    Inventors: Olivier Coutelou, Michel Clemence, Jean-Luc Bertocchi
  • Patent number: 9476922
    Abstract: According to one embodiment, a measuring device includes a clock output unit, a receiving unit, an adjusting unit, a generating unit, and a transmitting unit. The clock output unit generates a clock, counts the clock, and outputs a count value. The receiving unit receives a first message including time information. The adjusting unit adjusts time at which acquires a physical amount on the basis of the time information included in the first message and the count value output from the clock output unit when the first message is received. The generating unit generates a second message including a value of the physical amount acquired at the adjusted time. The transmitting unit transmits the second message to a device, which is a transmission source of the first message.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: October 25, 2016
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yasuyuki Kozakai, Kotaro Ise, Shigeki Katayama
  • Patent number: 9473036
    Abstract: A direct current voltage conversion device includes a buck converter receiving a direct current input voltage and outputting a direct current first voltage according to a first control signal, a series resonant converter outputting an alternating current second voltage according to a second control signal and a third control signal, a transformer that receives the alternating current second voltage, a rectifier, and an output capacitor electrically coupled with the rectifier. The rectifier generates a direct current output voltage according to a fourth control signal and a fifth control signal, which is outputted across the output capacitor.
    Type: Grant
    Filed: February 2, 2015
    Date of Patent: October 18, 2016
    Assignees: Lite-On Electronics (Guangzhou) Limited, Lite-On Technology Corp.
    Inventors: Wei-Lieh Lai, Ko-Fu Chou, Yi-Pin Lee
  • Patent number: 9008982
    Abstract: The present disclosure provides systems and methods for calculating the flux in a core of an unloaded power transformer using current measurements taken from a capacitance-coupled voltage transformer (CCVT) attached to the same phase line as the power transformer. According to various embodiments, the current sensors may both be positioned at zero-voltage points in the CCVT, eliminating the need for high-voltage insulated current sensors. An intelligent electronic device (IED) may determine the magnetic flux within the core of the power transformer using the measured and/or derived currents through capacitive assemblies of the CCVT. The IED may calculate the residual flux in the power transformer when it is de-energized. The IED may use the calculated residual flux to facilitate an optimized re-energization of the power transformer, thereby reducing inrush currents during re-energization.
    Type: Grant
    Filed: March 9, 2012
    Date of Patent: April 14, 2015
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventor: Demetrios A. Tziouvaras
  • Patent number: 8861155
    Abstract: A high-impedance system that utilizes asynchronous, line-mounted single-phase current and voltage sensors with rolling data logs and a common clock or other event trigger to synchronize the signals to a common time scale whenever a fault event is detected. The use of asynchronous, single-phase current and voltage angle sensors with rolling data logs, along with a common clock to synchronize the signals to common time scale whenever a fault event is detected, avoids the need for simultaneous three-phase current measurement. Integration of information, triggered by the detection of a loss or sufficient change of current on three or four (with a neutral current) devices, is used to determine the presence and direction of high-impedance faults and then report it, typically to a central control center via SCADA or another communication system, which implements fault isolation.
    Type: Grant
    Filed: April 17, 2013
    Date of Patent: October 14, 2014
    Assignee: Southern States, LLC
    Inventor: Joseph R. Rostron
  • Patent number: 8823356
    Abstract: Processes, machines, and articles of manufacture that may serve to enable the detection or determination of alternating line voltages from an alternating power source, such as the power grid, are provided. This automatic sensing may be useful when connections are made to the power grid, such that when connections are made, the connections may be configured to be compatible with the available power source. This automatic sensing may also be useful if power sources change characteristics over time or if devices may be connected to different power sources over time.
    Type: Grant
    Filed: March 21, 2011
    Date of Patent: September 2, 2014
    Assignee: SolarBridge Technologies, Inc.
    Inventor: Patrick L. Chapman
  • Publication number: 20140002937
    Abstract: A method in a three-terminal differential protection includes measuring a terminal phase current (IT1(y), IT2(y), IT3(y)) at each terminal (T1, T2, T3) of a protected zone of the differential protection in each phase (L1, L2, L3) to be protected, and determining a bias current (Ib(y)) of the phase on the basis of the terminal phase currents (IT1(y), IT2(y), IT3(y)). The bias current determination includes subtracting phasor values of the terminal phase currents of two terminals from the phasor value of the terminal phase current of one terminal. The terminal phase current, which is a minuend in the phasor difference computation, is selected on the basis of the phase angles or amplitudes of the terminal phase currents.
    Type: Application
    Filed: June 27, 2013
    Publication date: January 2, 2014
    Inventors: Mika TAUSA, Kari VANHALA
  • Patent number: 8433528
    Abstract: A ground fault detection system is provided. The ground fault detection system includes a magnetic core having first and second primary legs and a secondary leg disposed between the first and second primary legs. The ground fault detection system also includes first and second primary windings disposed around the first and second primary legs respectively and configured to introduce current in the first and second primary legs. Further, the ground fault detection system includes first and second secondary windings disposed around the first and second primary legs respectively and configured to detect a ground fault based upon a magnetic flux generated in response to the introduced current.
    Type: Grant
    Filed: December 18, 2009
    Date of Patent: April 30, 2013
    Assignee: Rockwell Automation Technologies, Inc.
    Inventors: Craig R. Winterhalter, Lixiang Wei, Zoran V. Vrankovic
  • Patent number: 8421475
    Abstract: The invention concerns a current sensor (22; 24; 26) for substantially in real time measuring electric current in a conductor. It is suitable for application in an indicator system (1) such as a short circuit indicator system for measuring instantaneous i.e. live current value, power, reactive power, phase angle, polarity, short circuits, in single or averaged values. It comprises current responsive means comprising a current transformer (2210), adapted for mounting adjacent to said electric conductor; and sensor circuitry (2220) comprising means for emitting a non-electrical wave signal as an output; said sensor circuitry (2220) comprises current level converter circuitry (2222) comprising a current-to-frequency converter adapted to provide said non-electrical wave signal as a current level indication pulse signal (CS1) having a pulse frequency (Pfcs) which is proportional to said real time electric conductor current, when the latter is within a predetermined current interval (I1-I2).
    Type: Grant
    Filed: July 6, 2007
    Date of Patent: April 16, 2013
    Assignee: Soren Thiim ApS
    Inventor: Søren Thiim
  • Patent number: 8415777
    Abstract: A circuit includes a plurality of integrated circuits or dies having corresponding circuits, the plurality of integrated circuits or dies include a first plurality of integrated circuits or dies having corresponding millimeter wave interfaces and a second plurality of integrated circuits or dies having corresponding inductive interfaces. The first plurality of integrated circuits or dies communicate first signals therebetween via the corresponding millimeter wave interfaces and the second plurality of integrated circuits or dies communicate second signals therebetween via the corresponding inductive interfaces.
    Type: Grant
    Filed: February 29, 2008
    Date of Patent: April 9, 2013
    Assignee: Broadcom Corporation
    Inventor: Ahmadreza (Reza) Rofougaran
  • Publication number: 20120224287
    Abstract: A relay for current differential protection of a transmission line, comprising: a first calculator of symmetrical sequence components of currents of each phase of the transmission line at local and remote ends of the transmission line; a second calculator of phase differences ?12 and ?012 between combinations currents i12 and i012 of the symmetrical sequence currents; a fuzzy inference system which outputs a variable y whose value is calculated according to the values of the phase differences ?12 and ?012; a third calculator which outputs a tripping signal for the control of a circuit breaker arranged on the transmission line and associated with the relay, the value of the tripping signal being calculated according to the values of the variable y and the values of the currents of each phase at the local and remote ends of the protected transmission line.
    Type: Application
    Filed: November 17, 2009
    Publication date: September 6, 2012
    Applicants: Schneider Electric Energy UK Ltd., Alstom Technology Ltd.
    Inventors: Waldemar Rebizant, Krzysztof Solak, Andrzej Wiszniewski, Andrzej Klimek
  • Patent number: 8217536
    Abstract: A first calculation part calculates the phase-to-phase steady-state magnetic flux of the three phases of the power supply. A second calculation part calculates the phase-to-phase residual magnetic flux of the three phases in the primary windings side of the transformer when the circuit breakers interrupt the transformer. A phase detection part detects a voltage phase at which polarity and magnitude of the calculated steady-state magnetic flux and residual magnetic flux coincide. Closing control part firstly causes only the circuit breakers of the two phases to close at the detected voltage phase, and then causes the circuit breaker of the remaining one phase to close.
    Type: Grant
    Filed: June 17, 2009
    Date of Patent: July 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadashi Koshizuka, Minoru Saito, Koichi Futagami, Hiroshi Kusuyama, Yoshimasa Sato
  • Patent number: 8054014
    Abstract: In a control system and a method for operating a permanent-magnet electrical machine, when the electrical machine is switched off after one of a functional computer and a monitoring computer of the control system has identified a fault, in order to reduce the braking torque of the electrical machine, which is switched-off but still rotating an output stage of the control system is subjected to a three-phase short circuit if the rotation speed D1 does not fall below a definable limit value GR1 or if a voltage U_DC of the output stage (2) exceeds a limit value Umax, and when the rotation speed D1 is below the definable limit value GR1 and a voltage U_DC of the output stage does not exceed a limit value Umax, all the circuits breakers (2o1, 2o2, 2o3, 2u1, 2u2, 2u3) of the output stage (2) are opened in order to fully disconnect the electrical machine from the output stage.
    Type: Grant
    Filed: October 17, 2008
    Date of Patent: November 8, 2011
    Assignee: Daimler AG
    Inventors: Lothar Rehm, Thomas Raumer
  • Publication number: 20110149446
    Abstract: An electronic protection system for motors is provided that includes electric current (SC1-n) sensor elements, more specifically Hall positioning sensors, and electronic circuits for electric tension reading. The signals are processed by a central processor (2) that executes a set of rules (A, B, C) and makes inferences based on the collected data in order to protect the motor (M, M?) against possible failure. Furthermore, a method to protect motors (M, M?) is provided, based on a set of rules (A, B, C) in order to characterize failures and trends of possible failures, so that the motor does not operate out of its specification for the system to deactivate it.
    Type: Application
    Filed: December 22, 2009
    Publication date: June 23, 2011
    Applicant: BITZER COMPRESSORES LTDA
    Inventor: Raphael Garcia MOREIRA
  • Patent number: 7812615
    Abstract: A method for fault detection in a power transformer/autotransformer and/or interconnected power lines, which are within the zone protected by the differential protection, and particularly suitable for detecting turn-to-turn faults in power transformer/autotransformer windings. All individual instantaneous phase currents of the protected object are measured, individual phase currents as fundamental frequency phasors are calculated, the contributions of the individual protected object sides negative sequence currents to the total negative sequence differential current are calculated by compensating for the phase shift of an eventual power transformer within the protected zone, the relative positions of the compensated individual sides negative sequence currents in the complex plane are compared, in order to determine whether the source of the negative sequence currents, i.e.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: October 12, 2010
    Assignee: ABB AB
    Inventors: Zoran Gajic, Ivo Brncic
  • Patent number: 7786735
    Abstract: A control system for an electrical power system includes an electrical corrective device, a voltage measuring device coupled to each phase of the electric power system, a current measuring device connected between each phase of the electric power system and the electrical corrective device, and a protective device connected to outputs of the voltage measuring device and the current measuring device. The protective device includes a controller configured to detect an imbalance using the measured voltages and currents output from the voltage measuring device and the current measuring device without using or independently of other recent voltage or current measurements for other points in the electrical corrective device and independently of a neutral-ground measurement at the electrical corrective device.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: August 31, 2010
    Assignee: Cooper Technologies Company
    Inventors: Aaron Kalyuzhny, John C. McCall, Timothy Robert Day
  • Patent number: 7732940
    Abstract: An apparatus for reducing a neutral current using a load switching method in accordance with the present invention includes a phase current detection unit for detecting a phase current in each of a top stage power line and a bottom stage power line, a load switching unit for changing an arrangement of a load connected each phase of at least one among the top stage power line and the bottom stage power line and a control unit for controlling the load switching unit so as to compare a strength of the detected phase current of the top stage power line with a strength of the detected phase current of the bottom stage power line and to change the arrangement of the load connected to each phase of at least one among the top stage power line and the bottom stage power line according to the comparison result.
    Type: Grant
    Filed: September 28, 2007
    Date of Patent: June 8, 2010
    Assignee: Sungkyunkwan University Foundation For Corporate Collaboration
    Inventors: Chul Hwan Kim, Keon Woo Park
  • Publication number: 20100053828
    Abstract: The present invention is directed to a protective relay for providing protective control to a power system carrying three-phase power. The protective relay performs a faulted phase detection method wherein signal values representative of electrical properties of the power carried by the power system are received and are processed to produce processed signals, respectively. The processed signals have components of the signal values removed that are the same frequency as the nominal operating frequency of the power system. The process signal values are added to produce a sum, which is then divided by a predetermined number to yield a quotient. A determination is made whether the quotient falls within one of a plurality of predetermined ranges. This determination is used to determine whether the power system has a single-phase fault, a two-phase fault, or a three-phase fault.
    Type: Application
    Filed: February 19, 2008
    Publication date: March 4, 2010
    Applicant: ABB TECHNOLOGY AG
    Inventor: Peter Selejan
  • Patent number: 7616005
    Abstract: A control system for an electrical power system includes an electrical corrective device, a voltage measuring device coupled to each phase of the electric power system, a current measuring device connected between each phase of the electric power system and the electrical corrective device, and a protective device connected to outputs of the voltage measuring device and the current measuring device. The protective device includes a controller configured to detect an imbalance using the measured voltages and currents output from the voltage measuring device and the current measuring device without using or independently of other recent voltage or current measurements for other points in the electrical corrective device and independently of a neutral-ground measurement at the electrical corrective device.
    Type: Grant
    Filed: October 17, 2005
    Date of Patent: November 10, 2009
    Assignee: Cooper Technologies Company
    Inventors: Aaron Kalyuzhny, John C McCall, Timothy Robert Day
  • Patent number: 7466113
    Abstract: A driver package includes an integrated circuit (IC) comprising pull up circuitry capable of turning ON an associated switch and pull down circuitry capable of turning OFF the associated switch. The pull up circuitry may be coupled to a first bonding pad of the IC, and the pull down circuitry may be coupled to a second bonding pad of the IC. The driver package may further comprise a first conductive path coupled between the first bonding pad and a package pin of the driver package, where the package pin is coupled to the associated switch, and a second conductive path coupled between the second bonding pad and the package pin. The first conductive path may further provide a sensed signal representative of state of the associated switch to break before make control circuitry to assist in minimizing a break before make delay time interval.
    Type: Grant
    Filed: July 7, 2004
    Date of Patent: December 16, 2008
    Assignee: 02Micro International Limited
    Inventors: Laszlo Lipcsei, Serban-Mihai Popescu
  • Patent number: 7319576
    Abstract: Provided is an apparatus and method for providing differential protection for a phase angle regulating transformer having a load side and a source side in a three-phase power system. The method includes calculating a first positive sequence component and a first negative sequence component associated with incoming secondary currents detected on the source side, calculating a second positive sequence component and a second negative sequence component associated with outgoing secondary currents detected on the load side, applying a phase angle shift to the second positive sequence component and the second negative sequence component to form a compensated positive sequence component and a compensated negative sequence component, respectively, and determining an operate current value and a restraint current value for each of a positive and negative sequence differential element of the differential protection based on the compensated positive sequence component and the compensated negative sequence component.
    Type: Grant
    Filed: August 18, 2005
    Date of Patent: January 15, 2008
    Assignee: Schweitzer Engineering Labortories, Inc.
    Inventor: Michael J. Thompson
  • Patent number: 7279905
    Abstract: A method of supervising the operation of a plurality of current transformers arranged in respective groups and connected to a protection relay forming part of a three-phase electrical power system includes determining a current ratio at an output of each group of current transformers, comparing each current ratio with a predetermined high ratio, comparing each current ratio with a predetermined low ratio, and generating a fault indication when the current ratio at one location exceeds the predetermined high ratio and the current ratio at the or each other location remains below the predetermined low ratio.
    Type: Grant
    Filed: February 21, 2006
    Date of Patent: October 9, 2007
    Assignee: Areva T&D UK Limited
    Inventor: Branislav Cvorovic
  • Patent number: 7196886
    Abstract: A resettable circuit interrupting device having a switch and timer circuit connected to the line side of the interrupting device to cause a leakage current to flow for a defined interval of time when power is applied. The timer and switch circuit comprises a timer powered by current from the phase leg of the device which is designed to operate for a defined interval of time. The timer starts operating when power is applied to the circuit interrupting device and normally continues to operate for the defined interval to time. Upon completion of the timed interval, the timer turns itself off and stays off until power is again applied to the device after an interruption. When power is first applied to the interrupting device, the timer is energized from the phase leg and causes the switch to close which connects the neutral leg on the line side of the interrupting device to a ground terminal.
    Type: Grant
    Filed: August 29, 2005
    Date of Patent: March 27, 2007
    Assignee: Leviton Manufacturing Co., Ltd.
    Inventors: David Chan, Steve Campolo
  • Patent number: 7106565
    Abstract: A directional ground relay (50) for receiving electric values relating to voltage and current from a power transmission line (1) to be protected. The directional ground relay may decide a direction of a fault in the power transmission line based upon the electric values. The directional ground relay comprises a zero-phase sequential current calculation unit (10-2) for calculating a zero-phase sequential current based upon the current detected from the power transmission line. The directional ground relay further comprises a phase-comparison unit (10-3) configured to compare a phase of the zero-phase sequential current to a phase of voltage corresponding to the voltage in the power transmission line, to decide whether the zero-phase sequential current is within a pre-determined range, and to output the phase of the voltage as a faulty phase of voltage, when the zero-phase sequential current is within the pre-determined range.
    Type: Grant
    Filed: July 21, 2003
    Date of Patent: September 12, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takahiro Kase, Yasutaka Sonobe, Hidenari Amo
  • Patent number: 6833711
    Abstract: The apparatus detects an out-of-step condition following the clearing of an external multi-phase fault in a protective relay. The apparatus includes a circuit which detects the presence of an external multi-phase fault on the power line and a timing circuit for readying an out-of-step logic detection circuit in the protective relay if the external fault remains for a pre-selected period of time. An out-of-step condition is declared and a signal blocking operation of selected distance elements in the protective relay is produced if the positive sequence impedance on the line remains inside an outer protection zone boundary in the impedance plane for a selected period of time, wherein the out-of-step blocking signal continues as long as the positive sequence impedance remains inside the second boundary.
    Type: Grant
    Filed: August 1, 2003
    Date of Patent: December 21, 2004
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Daqing Hou, Joseph E. Mooney
  • Patent number: 6785105
    Abstract: The fault detection system includes at least one valid zero sequence voltage source, either from a local relay or a remote relay on a protected line. Zero sequence current is selected between total (vector sum from both ends of the protected line) measured zero sequence current or calculated zero sequence current. A zero sequence impedance-based calculation is then made and the result is compared against a threshold value to produce a trip decision. The trip decision is then applied through a normal tripping circuit or a slow tripping circuit, depending upon selected circuit conditions, involving the local and remote ends of the line.
    Type: Grant
    Filed: August 5, 2002
    Date of Patent: August 31, 2004
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Jeffrey B. Roberts, David E. Whitehead
  • Patent number: 6720749
    Abstract: A three-phase motor protector uses two toroids to monitor all three phases of a three-phase motor. Current and phase loss are monitored directly in phases A and B while the phase C current level is determined by analysis of the phase A and B relationship. Current is induced into the phase A and B toroids from the motor supply lines with the resulting wave fed to an input of high-gain inverting amplifiers to provide A and B square waves which are inputted to separate channels of a microprocessor (U3). The square waves are processed by an AND gate providing an output square wave with a 16.66 percent duty cycle for normal operation. Upon loss of phase C the ANDed result is a digital low since the individual waves of phases A and B become an inverse of one another. In order to prevent nuisance tripping an AND output of less than 2 percent duty cycle is treated as a phase loss.
    Type: Grant
    Filed: September 27, 2002
    Date of Patent: April 13, 2004
    Assignee: Texas Instruments Incorporated
    Inventors: Timmy M. Ta, Marc P. Dupre
  • Patent number: 6671151
    Abstract: A network protector relay controls a circuit breaker connected between polyphase feeder and network busses. A circuit samples polyphase circuit breaker current and network voltage to generate digital polyphase current and voltage samples. A microcontroller generates positive sequence current and voltage vectors from the current and voltage samples. A first trip algorithm trips the breaker in response to the positive sequence current vector being in a first trip region of a first trip characteristic with respect to the positive sequence voltage vector. The first trip characteristic is defined by a reverse trip setpoint and a first positive angle. A second trip algorithm trips the breaker in response to the positive sequence current vector being in a second trip region of a second trip characteristic with respect to the positive sequence voltage vector. The second trip characteristic is defined by the reverse trip setpoint and a second negative angle.
    Type: Grant
    Filed: October 3, 2001
    Date of Patent: December 30, 2003
    Assignee: Eaton Corporation
    Inventors: David Robert Smith, John Robert Moffat, Jr., Thomas Joseph Kenny
  • Patent number: 6573726
    Abstract: A system for detecting ground faults in a compensated electric power distribution network includes the determination of zero sequence voltage (V0) and zero sequence current (I0) on a power line and calculating the zero sequence conductance (G0) therefrom. The operation of the conductance calculation circuit occurs only under selected power line conditions involving minimum values of zero sequence voltage, zero sequence current and positive sequence voltage, to ensure the accuracy of a fault direction determination. The conductance values are processed on an adaptive basis in which the difference between the most recent conductance value and a conductance value from a selected previous point in time is determined and then compared against threshold values to make forward and reverse fault declarations.
    Type: Grant
    Filed: May 2, 2000
    Date of Patent: June 3, 2003
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Jeffrey B. Roberts, Daqing Hou, Hector Altuve-Ferrer
  • Patent number: 6504693
    Abstract: A network protector relay for a circuit breaker includes a microcontroller routine which provides a positive sequence network voltage from polyphase network voltages on a network bus. Another microcontroller routine provides a positive sequence phasing voltage from the polyphase network voltages on the network bus and polyphase feeder voltages on a feeder bus. A recloser circuit automatically recloses the circuit breaker connected between the polyphase feeder bus and the polyphase network bus in response to a function of a plurality of setpoints and the positive sequence phasing voltage which indicates a first flow of power from the polyphase feeder bus to the polyphase network bus. A receiver receives a remote close command.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: January 7, 2003
    Assignee: Eaton Corporation
    Inventors: John R. Moffat, John C. Schlotterer, Thomas J. Kenny, David M. Oravetz
  • Patent number: 6493203
    Abstract: A phase control switch apparatus incorporating a phase-based break/make controller (80A, 80B, 80C) for protecting a reactive load such as a transformer (10) from transient surge phenomena taking place upon power-supply breaking/making operation.
    Type: Grant
    Filed: November 22, 2000
    Date of Patent: December 10, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hiroki Ito, Masaki Hiratsuka, Haruhiko Kohyama
  • Publication number: 20020149893
    Abstract: A protection relay for determining whether or not a faultal point of a power system exists in a predetermined range, comprises filter section for inputting sampling data of a voltage and a current in the power system to a digital filter having a predetermined transfer function and outputting a first voltage data and a first current data, and a second voltage data and a second current data normal to the first voltage data and the first current data, respectively, calculator for calculating a predetermined measurement value based on the first and second voltage data, and the first and second current data at a first time and the first and second voltage data, and the first and second current data at a second time different from the first time, and operation decision section for performing an operation decision based on the predetermined measurement value obtained by the calculator.
    Type: Application
    Filed: March 1, 2002
    Publication date: October 17, 2002
    Inventors: Yasuhiro Kurosawa, Hidenari Amo, Hideyuki Takani
  • Patent number: 6392858
    Abstract: The trip device with phase reconstitution comprises a processing unit comprising means for phase reconstitution receiving signals representive of the current signals supplied by sensors. The means for phase reconstitution comprise means for determining signals representative of the amplitudes of the current signals supplied by the two sensors, means for determining a signal representative of a phase shift between signals representative of the signals supplied by the two sensors and means for determining a signal representative of a phase current reconstituted according to the signals representative of the amplitudes and to the signal representative of a phase shift of the signals supplied by the two sensors. The circuit breaker comprises such a trip device.
    Type: Grant
    Filed: March 6, 2000
    Date of Patent: May 21, 2002
    Assignee: Schneider Electric Industries SA
    Inventor: Dominique Boudaud
  • Patent number: 6175810
    Abstract: A method for generating a signal identifying a three-pole short-circuit occurring in a three-phase power transmission line in which the phase currents and phase voltages are sampled forming phase current and phase voltage sampling values and the signal is formed from the phase current and phase voltage sampling values. In order to reliably detect three-phase short-circuits with such a method, even during oscillations, a positive phase-sequence system effective power parameter that is proportional to the instantaneous value of the positive phase-sequence system effective power of the power transmission line is formed, from which a grid frequency component parameter and a swing component parameter are then determined. The signal is generated from the grid frequency component parameter and the swing component parameter.
    Type: Grant
    Filed: September 28, 1998
    Date of Patent: January 16, 2001
    Assignee: Siemens AG
    Inventor: Andreas Jurisch
  • Patent number: 6154687
    Abstract: A high sample rate cosine filter eliminates DC components by summing them such that they sum to zero. A non-orthogonal cosine filter is also provided. When the cosine filter is applied for N=4 samples per cycle, the samples are separated by 90 degrees. However, at higher sampling rates, it is not necessary to wait for 90 degrees to estimate the phasor value. Non-orthogonal components are used to estimate the phasor value. The time delay associated with the cosine filter is reduced in the process.
    Type: Grant
    Filed: April 15, 1998
    Date of Patent: November 28, 2000
    Assignee: ABB Power T&D Company Inc.
    Inventors: David G. Hart, Damir Novosel, Robert A. Smith
  • Patent number: 6147616
    Abstract: The present invention provides a digital automatic power interruption and re-supply relay for performing detection and comparing operation to inform a state of an accident with voice and numerals and automatically operating a connected relay to interrupt power when there occur abnormal changes such as interruption of electric power, open-phase, anomalous voltage, unbalanced voltage, negative-phase, overcurrent, and electric leakage in a power transmit and supply line of high and low voltage or special high voltage and high (low) voltage and, after compensating for the accident, for automatically re-supplying the power.
    Type: Grant
    Filed: March 23, 1999
    Date of Patent: November 14, 2000
    Inventor: Myung Dong Kim
  • Patent number: 6114859
    Abstract: Single-phase currents at two frequencies f.alpha. and f.beta. (f.alpha.<n.multidot.fs<f.beta.) of non-integral multiples of a system fundamental wave frequency fs sandwiching an targeted harmonic (frequency n.multidot.fs) are injected between two phases of a three-phase power system as interharmonic currents. A frequency analysis of measurement current and measurement voltage of each phase in the system is carried out and a positive-phase-sequence current I1, a positive-phase-sequence voltage V1, a negative-phase-sequence current I2, and a negative-phase-sequence voltage V2 are detected for each of the two frequencies f.alpha. and f.beta. in the system based on injecting of the interharmonic currents. Positive-phase-sequence and negative-phase-sequence admittances Y1 and Y2 or positive-phase-sequence and negative-phase-sequence impedances Z1 and Z2 are found for each of the frequencies f.alpha. and f.beta. in the system as Y1=I1/V1 and Y2=I2/V2 or Z1=V1/I1 and Z2=V2/I2.
    Type: Grant
    Filed: July 13, 1998
    Date of Patent: September 5, 2000
    Assignees: Nissin Electric Co., Ltd., Chuba Electric Power Co., Inc.
    Inventors: Isao Koda, Masakazu Tsukamoto, Yasuhiro Fuwa, Shoji Nishimura, Yoshifumi Minowa, Yasuyuki Natsuda
  • Patent number: 6104106
    Abstract: A switching circuit that is particularly applicable to high voltage 3 phase solid state circuit breakers (SSCB). The circuit comprises a solid state switch; an energy absorbing device connected in parallel with said switch to form a parallel combination; an inductor connected in series with said parallel combination; and a control circuit connected to said solid state switch and adapted to turn off said switch in response to a predetermined voltage/current condition.
    Type: Grant
    Filed: July 8, 1997
    Date of Patent: August 15, 2000
    Inventor: Donald F. Partridge
  • Patent number: 6064001
    Abstract: Two molded case electrical switches such as circuit breakers, network protectors, disconnect switches and transfer switches, are secured together side-by-side by joining blocks having tongues extending along their sidewalls which engage undercutting grooves undercutting the irregular surfaces of the confronting sidewalls of the switch molded casings with an interference fit. Separate joining blocks for the front and rear sections of the molded casing are driven into place and retained by bolts engaging flanges on the molded casing. The poles are paralleled by external conductors in any desired configuration so that the standard switches can be used without customization.
    Type: Grant
    Filed: May 7, 1998
    Date of Patent: May 16, 2000
    Assignee: Eaton Corporation
    Inventors: Phillip L. Ulerich, William J. Jones, Norman J. Phillips, Frank Roth
  • Patent number: 5883796
    Abstract: A method and apparatus is provided for restoring a sagging voltage signal on a power transmission line, caused by a remote fault in the utility power system, to a balanced three-phase condition at the pre-fault voltage level. Voltage restoration is provided by injecting a voltage signal in series with the power transmission line which restores the load voltage vectors to the pre-fault condition. The restored load voltage vectors are rotated by a selected phase angle such that zero real power flow is associated with the voltage restoration. The voltage compensation signal may be injected into the power transmission line by connecting a voltage compensator inverter in series with the transmission line. The voltage compensator inverter may be controlled to provide the desired injected voltage signal using a synchronous reference frame based controller.
    Type: Grant
    Filed: April 7, 1997
    Date of Patent: March 16, 1999
    Assignee: Wisconsin Alumni Research Foundation
    Inventors: Po-Tai Cheng, Robert H. Lasseter, Deepakraj M. Divan
  • Patent number: 5883578
    Abstract: The positive sequence voltage on the power line is measured at a given time, i.e. the present time, and also for one cycle earlier, and the ratio thereof is then compared against a threshold value of 0.9. There are four other supervisory tests which also must be true for a loss of potential condition to be indicated. These include determination of change in positive sequence current and angle and zero sequence current and angle. If the change in those values is smaller than selected thresholds, then a loss of potential condition is indicated.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: March 16, 1999
    Assignee: Schweitzer Engineering Laboratories, Inc.
    Inventors: Jeffrey B. Roberts, Daging Hou
  • Patent number: 5859530
    Abstract: In a first measurement step, the two test probes of a measurement apparatus are contacted with two of the three phase lines. The measurement apparatus determines the frequency of the three-phase voltage. In a subsequent second measurement step, one of the two test probes is brought into connection with the remaining third phase line. The other test probe is held in contact with the other line. In the second measurement step the voltage level or voltage profile on the third phase line is evaluated inside the measurement apparatus in comparison to the first phase line during one or more time windows of length .pi..
    Type: Grant
    Filed: September 25, 1996
    Date of Patent: January 12, 1999
    Assignee: Ch. Beha GmbH Technische Neuentwicklungen
    Inventor: Christian Beha
  • Patent number: 5822165
    Abstract: A digital network protector relay samples the polyphase current, network voltage and phasing voltage at 16, and preferably 32, times per cycle so that up to the seventh and fifteenth harmonics, respectively, are eliminated from the sequence calculation used to make trip and close decisions. The relay also provides metering, forward overcurrent protection, and an anti-pumping feature, the latter of which locks the circuit breaker out if a selected number of breaker operations is exceeded during a given time interval. Sequential sampling of the polyphase current and voltages by a single analog to digital converter reduces the cost of the relay. In order to accommodate metering and extraction of the fundamental components of the current and voltages for the sequence calculations, the polyphase current and network voltage are sampled sequentially in a first order for a given number of cycles and then in a second reverse order for the same given number of cycles.
    Type: Grant
    Filed: September 16, 1996
    Date of Patent: October 13, 1998
    Assignee: Eaton Corporation
    Inventor: Steven Alan Moran
  • Patent number: 5784240
    Abstract: A method of and apparatus for actuating an automatic transfer switch for disconnecting a motor load from a normal source of voltage and reconnecting the load to an alternate source of voltage at a time when phase differences between the output voltage of the disconnected motor load and of the alternate source voltage are minimized to prevent excessive in-rush currents to the motor upon reconnection. Actuation of the transfer switch is commenced when the difference in phase between the normal source and alternate source is equal to a predetermined number of degrees depending upon whether the alternate source frequency is greater or less than the normal source frequency.
    Type: Grant
    Filed: December 20, 1996
    Date of Patent: July 21, 1998
    Assignee: Automatic Switch Company
    Inventor: Walter Przywozny
  • Patent number: 5777835
    Abstract: A method and apparatus are disclosed to reconstruct a third phase for a three phase sensing system in which only two current transformers sense all three phases. Two phases of the three phase system are used as a single primary winding for each current transformer such that each current transformer produces a voltage representation of a sum of two phase currents. The present invention is directed toward reconstructing the third phase from the two discrete signals produced so that true RMS characteristics can be determined, as well as indicating any phase loss. Since all three phases can then be represented, this technique offers precise phase imbalance protection as well.
    Type: Grant
    Filed: June 30, 1997
    Date of Patent: July 7, 1998
    Assignee: Eaton Corporation
    Inventor: Mark E. Innes
  • Patent number: 5768079
    Abstract: An adaptive method and apparatus for detecting fault conditions in a power distribution system that services both single phase loads and three phase loads. The present invention accomplishes this by providing an adaptive ground fault detection method and an adaptive phase fault detection method. Both methods provide the capability to distinguish gradual changes in phase current, due to ordinary current fluctuations, from more substantial changes in phase current due to various fault conditions. By making this distinction, the present invention minimizes unnecessary service interruptions.
    Type: Grant
    Filed: September 25, 1996
    Date of Patent: June 16, 1998
    Assignee: Cooper Industries, Inc.
    Inventor: Richard Ralph Buell
  • Patent number: 5751132
    Abstract: An electric motor monitoring circuit apparatus for an electric motor has a three phase electric motor having an electric motor starter circuit. An insulation monitoring circuit is coupled to the electric motor and monitors insulation leakage of the electric motor and inhibits activation of the electric motor starter circuit when an insulation leakage exceeds a preselected threshold. A three phase monitor circuit is coupled to the electric motor for monitoring phase sequence in voltage amplitude for the electric motor.
    Type: Grant
    Filed: September 20, 1996
    Date of Patent: May 12, 1998
    Assignee: Automeg, Inc.
    Inventors: Joseph G. Horvath, James C. Miller
  • Patent number: 5710542
    Abstract: A method for measuring the current in an AC power transmission network, where a measurement quantity is obtained by means of a current transformer and digital samples are converted. To prevent faulty detection of the current due to a decaying DC component of the current transformer, two initial auxiliary measurement quantities that are normal to one another are formed from the digital samples by means of at least two FIR filters, and together with two additional auxiliary measurement quantities that are normal to each other, are used to produce a measured value corresponding to the amplitude of the current. The additional auxiliary measurement quantities are produced from samples formed from an older measurement quantity obtained earlier by a quarter period of the current to be measured. The differential angle is formed from the two measurement quantities. An output signal is generated from the two measured values in an evaluation device when the measured values exceed preset threshold values.
    Type: Grant
    Filed: November 12, 1996
    Date of Patent: January 20, 1998
    Assignee: Siemens Aktiengesellschaft
    Inventor: Andreas Jurisch