Transformer Protection Patents (Class 361/35)
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Patent number: 8441264Abstract: A detecting station of a winding product and a method for detecting an inter-turn short circuit are provided. The method includes following steps. First, a high voltage pulse is input to two ends of a winding of a winding product. Next, a voltage value of an electrifying process of the winding is extracted for generating an extracting data. Finally, a time-frequency converting operation is performed to the extracting data, and a time-frequency analysis information is generated for indicating whether or not the inter-turn short circuit is occurred in the winding.Type: GrantFiled: December 15, 2009Date of Patent: May 14, 2013Assignee: Industrial Technology Research InstituteInventors: Chun-Chieh Wang, Yu-Liang Chung, Yong-Lin Kuo, Lai-Sheng Chen
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Patent number: 8351169Abstract: The present invention relates to a system and method for preventing, protecting OLTC from fire and/or preventing, protecting and/or detecting explosion and/or resulting fire of electrical transformer (30) in advance before decomposition of combustible coolant fluid (11)/dielectric oil.Type: GrantFiled: January 1, 2009Date of Patent: January 8, 2013Assignee: CTR Manufacturing Industries LimitedInventor: Vijaykumar Kisanrao Wakchaure
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Patent number: 8345399Abstract: An electrical protection assembly for connection between an electrical power supply line and electrical equipment has an insulating mounting structure; a first arm connectable to a live conductor for connection to a fusible device at a first end and a voltage surge protection unit at a second end, pivotally attached to the mounting structure in a displaceable manner intermediate its ends; a first connection arrangement at the first end of the first arm for connection to the fusible device; and a second connection arrangement at the second end of the first arm for connection to the voltage surge protection unit. The assembly further includes first and second springs for urging the first arm relative to the mounting structure. The springs may urge the second connection arrangement towards the voltage surge protection unit and the first connection arrangement away from the fusible device.Type: GrantFiled: September 30, 2010Date of Patent: January 1, 2013Assignee: The Trustees for the Time Being of the Philip Edward Lawrence Risi TrustInventor: Philip Edward Lawrence Risi
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Patent number: 8344557Abstract: The present invention provides a magnetic flux measuring device and magnetic flux measuring method for stationary induction electrical apparatus which can accurately measure the magnetic flux without being influenced by the DC offset component which superimposes on the measurement system, and can constantly and continuously measure the magnetic flux without setting a limit in the magnetic flux measurement period. The magnetic flux measuring method which measures a magnetic flux of a stationary induction electrical apparatus 2 using a voltage waveform of the stationary induction electrical apparatus 2, wherein the magnetic flux 151 of the stationary induction electrical apparatus 2 is determined by the steps of: inputting a voltage waveform 121 of the stationary induction electrical apparatus 2 into a negative-feedback amplification means 14 of which feedback circuit is constructed by a low pass filter; and integrating output of the negative-feedback amplification means 14 by integration means 15.Type: GrantFiled: October 12, 2007Date of Patent: January 1, 2013Assignee: Kabushiki Kaisha ToshibaInventor: Minoru Saito
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Patent number: 8331066Abstract: A circuit breaker for a transformer includes means for interrupting circuitry in the transformer upon a fault condition in the transformer (the “fault interruption means”). The circuit breaker also includes means for interrupting the circuitry when a level of dielectric fluid in a tank of the transformer is unacceptably low (the “low oil trip means”). The fault interruption means includes a magnet, metal element, and first actuator. Upon the fault condition, the magnet and metal element separate, moving the first actuator to cause the electrical circuitry to open. The low oil trip means includes a float, insulating rod, and second actuator. When the dielectric fluid level drops to an unacceptably low level, the float and insulating rod drop, moving the second actuator to cause the circuitry to open. The low oil trip means operates independently of the fault interruption means, opening the circuitry without separating the magnet and metal element.Type: GrantFiled: December 3, 2009Date of Patent: December 11, 2012Assignee: Cooper Technologies CompanyInventor: Nicholas Paul Brusky
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Publication number: 20120293896Abstract: An inrush-current suppressing device includes a residual-magnetic-flux calculation unit that obtains a residual magnetic flux generated within a three-phase transformer, an input magnetic-flux-error calculation unit that obtains a closing-phase input magnetic-flux error, a closing-order determination unit that determines a closing order of phases of a three-phase breaker, a target-closing-phase/time setting unit that sets a time from a reference point to a target closing phase of a first closing phase as a first target closing time, and sets a time obtained by adding up a time from the reference point to a target closing phase of a second closing phase and a delay time set to exclude a period in which a magnetic flux in the first closing phase possibly saturates as a second target closing time, and a closing control unit that generates and outputs a closing control signal to close each phase at the target closing time.Type: ApplicationFiled: April 8, 2010Publication date: November 22, 2012Inventors: Tomohito Mori, Haruhiko Koyama, Aya Yamamoto
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Patent number: 8310106Abstract: To suppress the magnetizing inrush current occurring when supplying power of three phases of the transformer are performed simultaneously using three single-phase circuit breakers or a non-phase segregated operation-type circuit breaker, without providing a circuit breaker with a resistor or other equipment. A magnetizing inrush current suppression method for transformer suppresses a magnetizing inrush current occurring at the start of energizing of a three-phase transformer 300, when a three-phase power supply 100 is input to a terminal of each phase by means of a three-phase circuit breaker 200.Type: GrantFiled: November 29, 2007Date of Patent: November 13, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Tadashi Koshiduka, Minoru Saito, Susumu Nishiwaki, Nobuyuki Takahashi, Koichi Futagami, Yoshimasa Sato, Tsuyoshi Kokumai, Hiroshi Kusuyama
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Patent number: 8300378Abstract: One form of the invention provides a method and apparatus for preventing an extraordinary electromagnetic pulse from reaching and rendering inoperative an electrical component of an electrical power system, wherein the component is located in a conductive path of the system that receives the pulse. The method and apparatus comprises the steps or means for detecting the presence of the pulse in the conductive path prior to the pulse reaching and rendering inoperative the electrical component. The pulse is diverted around the electrical component with a low inductance, high current capacity circuit relative to the electrical component before the pulse can reach and render the electrical component inoperative. The foregoing invention may beneficially utilize a high-speed current shunt comprising a flat conductive metal strap having a defined current-measuring region, a tapered parallel-plate transmission-line matching transformer attached to the current-measuring region and an output via a coaxial cable.Type: GrantFiled: March 16, 2010Date of Patent: October 30, 2012Assignee: Advanced Fusion Systems, LLCInventor: Curtis A. Birnbach
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Patent number: 8274769Abstract: The cooling system for a power transformer is activated by sensing and processing the frequency characteristic including the harmonic contents, of the inrush current into the transformer, when the transformer is first energized. The cooling system may include motors operating devices such as oil circulating pumps and fans causing a coolant to flow about the power transformer. The cooling system is deactivated by sensing when the transformer is de-energized and when its temperature is below a predetermined level.Type: GrantFiled: June 7, 2010Date of Patent: September 25, 2012Assignee: Advanced Power Technologies, LLCInventors: Gary R. Hoffman, Jeffrey Anderson
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Publication number: 20120236442Abstract: Described herein is an intelligent controller for management and control of electrical distribution transformer either located within the transformer or outside the transformer, housed in a separate enclosure and mainly comprising: a. input terminals (3,4) wherein the distribution transformers output is terminated; b. output terminals wherein the load is terminated (3.8(1), 3.8(2)); c. a power supply derived internally; d. a set of built-in contactors (3.7(1), 3.7(2)) to control the load; e. a set of in-built transducers, programmable digital input and output terminals; f. a communicable Real Time Embedded System (3.11) whose Operating characteristics can be programmed either through a local MMI or through a wired &/wireless communication interface after proper user authentication; and g. a capacitor (3.9(1), 3.9(2)) to improve the PF of the load, said-capacitor bank (3.9(1), 3.9(2)) is controlled by the RTES (3.11).Type: ApplicationFiled: December 2, 2009Publication date: September 20, 2012Inventors: Manchanahally Venkataramasastry Satyanarayana, Srikanth Kashyap Satyanarayana
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Patent number: 8217536Abstract: 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: GrantFiled: June 17, 2009Date of Patent: July 10, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Tadashi Koshizuka, Minoru Saito, Koichi Futagami, Hiroshi Kusuyama, Yoshimasa Sato
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Publication number: 20120162829Abstract: A stand-alone circuit breaker assembly that includes a housing having a plurality of openings, a plurality of first bushings mounted through the openings in the housing for receiving electrical power from the distribution transformer, at least one circuit breaker, each circuit breaker having a plurality of input terminals and a plurality of output terminals, wherein the at least one circuit breaker is located inside the housing, a plurality of first electrical connectors electrically connected in one-to-one correspondence between the plurality of first bushings and the plurality of input terminals, a plurality of second bushings mounted through the openings in the housing for providing electrical power through the at least one circuit breaker, and a plurality of second electrical connectors electrically connected in one-to-one correspondence between the plurality of second bushings and the plurality of output terminals. The stand-alone circuit breaker can be utilized with a distribution transformer.Type: ApplicationFiled: November 11, 2011Publication date: June 28, 2012Applicant: H-J INTERNATIONAL, INC.Inventors: Etelvino L. Heres, Gabriel Alvarez Del Prado
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Patent number: 8179654Abstract: A surge preventing circuit of a local area network (LAN) connector is suitable for being coupled to a plurality of transformers disposed in the local area network connector. The surge preventing circuit includes a conjugate coil module and a surge absorbing element. The conjugate coil module has at least one conjugate coil. The conjugate coil has a first input terminal, a second input terminal, a first output terminal, and a second output terminal. The first input terminal and the second input terminal of the conjugate coil are coupled to the center tapped terminal of the respective transformer, respectively. A first terminal of the surge absorbing element is connected to ground, and a second terminal is coupled to the first output terminals and the second output terminals.Type: GrantFiled: December 9, 2009Date of Patent: May 15, 2012Assignee: Unihan CorporationInventors: Wei-Chun Tsao, Yu-Hsiang Li
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Patent number: 8155902Abstract: A sensor-less technique is described for detecting the status of an AC contactor of a power inverter. In one embodiment, a method is provided of sensing an unexpected condition of an AC contactor used to couple to a power distribution system a power inverter having at least one power conductor. The method includes determining a voltage value for the conductor; determining a current value for the conductor; determining a phase difference using the voltage value and the current value; and monitoring successive values of the phase difference to produce a monitoring result. Depending on the monitoring result, a determination is made whether or not to issue an alert signal. Control routines embodying such technique may be stored on computer-readable media. A power inverter using such technique is described.Type: GrantFiled: October 8, 2008Date of Patent: April 10, 2012Assignee: Xantrex Technology Inc.Inventors: Jun Yin, Renjie Xu
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Patent number: 8149550Abstract: A protective device is disclosed having a circuit breaker for an electrical connection between a transformer and a load, wherein an overcurrent device is arranged between the transformer and the load. The overcurrent device has first magnetoelectric transducers arranged at each phase conductor and the neutral conductor, wherein the overcurrent device uses the transducer currents to in each case establish the presence of a first ground-fault current, and wherein the circuit breaker has a switching device, which interrupts at least the phase conductors between the transformer and the load in the event of the presence of a first ground-fault current (unrestricted earth fault).Type: GrantFiled: December 27, 2006Date of Patent: April 3, 2012Assignee: Siemens AktiengesellschaftInventors: Henry Franke, Jeffery C. Mizener, Ilka Redmann
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Publication number: 20120050923Abstract: A protected electrical power system may comprise a feeder between a power source and an electrical load. A first current transformer may be positioned on the feeder in a first location. The first current transformer may have a shunt resistor electrically connected across its winding. A second current transformer may be positioned at a second location on the feeder. A control unit may be interposed between the first and second current transformers and may be interconnected with the first and second current transformers on current-monitoring loops independent from the feeder. The control unit may be responsive to a predetermined differential in feeder (DF) current between the first and second current transformers to disconnect the power source from the electrical load. The control unit may have a compensation network for reducing DF error resulting from presence of the shunt resistor in the first current transformer.Type: ApplicationFiled: August 30, 2010Publication date: March 1, 2012Applicant: HONEYWELL INTERNATIONAL INC.Inventors: RANDY FULLER, DAVID HODGE, JAMES LOBSINGER
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Publication number: 20120026630Abstract: An instrument transformer includes a current transformer configured to be coupled to a load, and to generate an analog signal that is proportional to a current flowing through the load. The instrument transformer also includes a protection module and a digitizer module that is coupled to the current transformer. The digitizer module is configured to receive an input signal that is proportional to the analog signal and to convert the input signal to a digital signal. The digitizer module includes a synchronization module for generating at least one timing signal and a fiber optic interface module coupled to the protection module and to the synchronization module for transmitting the digital signal to the protection module.Type: ApplicationFiled: July 30, 2010Publication date: February 2, 2012Inventor: Peter E. Sutherland
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Publication number: 20120008239Abstract: The transformer module of the invention includes an isolation transformer having a primary winding with a first tap and a secondary winding with a second tap. A protection circuit is electrically connected to the first tap and the second tap. The protection circuit includes at least one protective element.Type: ApplicationFiled: May 20, 2011Publication date: January 12, 2012Inventor: Nai-Chien CHANG
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Patent number: 8049301Abstract: A planar transformer structure, which can be constructed in an integrated semiconductor circuit without using traditional metallic windings. To avoid large thermal expansion of metallic spiral windings and associated mechanical stress on a metal-semiconductor interface, it is suggested that highly doped semiconductor materials with or without silicides and salicides can be used to form windings or conducting paths because their thermal expansion coefficients are similar to that of semiconductor material. The planar semiconductor transformer may find application for low-power and signal transfer that needs electrical isolation.Type: GrantFiled: September 21, 2007Date of Patent: November 1, 2011Assignee: City University of Hong KongInventor: Shu Yuen Ron Hui
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Patent number: 8044624Abstract: A load control apparatus outputs a PWM signal to a switching element to control a load. The switching element is connected between a power supply and a grand in series with the load. An abnormal increase detecting unit outputs an abnormal increase detection signal when detecting abnormal increase in applied voltage, which is applied to the load, relative to target voltage. An abnormal decrease detecting unit outputs an abnormal decrease detection signal when detecting abnormal decrease in the applied voltage relative to the target voltage. An operating state monitoring unit outputs a normally operating signal when the load normally operates. A signal combining unit generates a combined signal by combining the abnormal increase detection signal, the abnormal decrease detection signal, and the normally operating signal and outputs the combined signal via a common signal output terminal.Type: GrantFiled: May 15, 2008Date of Patent: October 25, 2011Assignee: DENSO CORPORATIONInventors: Yosuke Matsuo, Shigeru Takeuchi, Taketoshi Sato
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Patent number: 8035941Abstract: A DC/AC inverter substrate includes a voltage abnormality detector circuit. All of a high voltage side detection sensor, a low voltage side detection sensor, and a high-voltage and low-voltage detection sensor in the voltage abnormality detector circuit are disposed without being electrically connected to a secondary side of a transformer or to a connection point. Those detection sensors are not damaged since overvoltage is not applied to the voltage abnormality detector circuit when abnormal discharge occurs because the detection sensors are not electrically connected.Type: GrantFiled: August 29, 2008Date of Patent: October 11, 2011Assignee: NEC LCD Technologies, Ltd.Inventor: Yuuichi Hasegawa
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Patent number: 8035935Abstract: A countermeasure for mitigating Electromagnetic Pulse E3 (EMP-E3) induced currents flowing through the neutral of a star-connected three-phase power transformer without compromising its neutral end insulation performance. It comprises an external neutral-grounding device; a first linear resistor (R10) is connected from the transformer neutral (N) to ground (G) sized to render said induced currents, for any given EMP-E3 severity, reduced and inconsequential to the equipment operation. Contingently, a second non-linear neutral-grounding resistor (R11) provides a shunting path-to-ground of substantially low resistance, as prevailing by virtue of its non-linearity under large power system fault currents; such a bypass functionality is formulated/designed according to IEEE/ANSI/NEMA recommended insulation coordination guidelines in order to sustain proper protective margins to the equipment neutral basic insulation levels (BIL/BSL).Type: GrantFiled: October 19, 2009Date of Patent: October 11, 2011Inventors: Vanessa Ramirez, Alberto Ramirez
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Patent number: 8031447Abstract: A device is provided for monitoring through-fault current in an electric transformer on an electrical power system. The device generally includes a magnitude calculator for calculating the magnitude of current (e.g., a root means square value of current or magnitude of a fundamental of current) based on the current through the electric transformer. A through-fault energy calculator is further provided which is coupled to the magnitude calculator for calculating a through-fault energy value based on the magnitude of current or the calculated current through the transformer. An accumulator is coupled to the through-fault energy calculator for accumulating a plurality of through-fault energy values, and an alarm coupled to the accumulator for indicating that the accumulated through-fault energy values exceed a selected threshold.Type: GrantFiled: October 8, 2008Date of Patent: October 4, 2011Assignee: Schweitzer Engineering Laboratories, Inc.Inventors: Armando Guzman-Casillas, Normann Fischer
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Patent number: 8024077Abstract: The present invention provides a system and computer program product for implementing a smart transformer, comprising a processor, and a balancing algorithm residing on the processor, wherein the balancing algorithm is stored on a non-transitory computer readable medium having computer executable program code embodied thereon, the computer executable program code configured to cause the system to monitor and control an electric customer load and generation in order to optimize the performance of a distribution transform wherein the processor receives a plurality of system inputs and uses the balancing algorithm to determine a rating of the transformer and an amount of customer load.Type: GrantFiled: October 6, 2010Date of Patent: September 20, 2011Assignee: San Diego Gas & Electric CompanyInventors: William Vincent Torre, Amanda Louise Myers, Michael James Colburn
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Patent number: 8023572Abstract: A communication interface employing a differential circuit and method of use is disclosed. In one form, a circuit operable to communicate signals via a communication bus can include a differential signaling circuit operable to be coupled to a communication bus. The differential signaling circuit can include a first current carrying element and a second current carrying element. The circuit can also include a shunt circuit including a first transformer. The first transformer can include a primary transformer element and a secondary transformer element. The first transformer can be operably associated with the communication bus.Type: GrantFiled: November 29, 2006Date of Patent: September 20, 2011Assignee: Dell Products, LPInventor: Jeffrey C. Hailey
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Publication number: 20110216450Abstract: A transformer failure analysis system using a programmable chip in conjunction with a shock response spectrum analysis method to distinguish inrush current and fault current of a transformer and to monitor the phase of an AC power source inputting to the transformer by means of a phase detector. When an inrush current occurs, the programmable chip provides a control signal to delay the phase of the AC power source being inputted into the transformer, thereby suppressing the occurrence of the inrush current. When a fault current occurs, the control signal cuts off the AC power source from the transformer until the operator has tested the whole circuit architecture to debug and correct circuit application and eliminated the internal fault.Type: ApplicationFiled: March 8, 2011Publication date: September 8, 2011Applicant: NATIONAL FORMOSA UNIVERSITYInventors: Chien-Lung Cheng, Shyi-Ching Chern, Jim-Chwen Yeh, Yi-Hung Lan, chen-Chang Yang
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Publication number: 20110181989Abstract: Inrush current suppression apparatus for suppressing a transformer inrush current including a transformer side voltage measurement unit which measures a voltage at a side of a transformer, a residual magnetic flux calculation unit which calculates three line-to-line residual magnetic fluxes, a power supply side voltage measurement unit which measures a voltage at a side of a power supply, a stable-state magnetic flux calculation unit which calculates three line-to-line stable-state magnetic fluxes, based on the voltage at the side of the power supply, a phase determination unit which determines a phase in which phases of the three line-to-line stable-state magnetic fluxes are respectively the same in polarity as phases of the three line-to-line residual magnetic fluxes, and a closing unit which closes the circuit breaker in the phase determined by the phase determination unit.Type: ApplicationFiled: January 27, 2011Publication date: July 28, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Keisuke UDAGAWA, Tadashi KOSHIZUKA, Shiro MARUYAMA, Minoru SAITO, Noriyuki NAGAYAMA
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Publication number: 20110128656Abstract: An overcurrent protection control circuit for an electronic transformer includes a feedback current detection circuit, an averaging circuit and an overcurrent shutdown circuit. The feedback current detection circuit detects feedback current of an output of the electronic transformer. The averaging circuit determines an average of the feedback current detected by the feedback current detection circuit. The overcurrent shutdown circuit is configured to shutdown the output of the electronic transformer based on the average of the feedback current exceeding a predetermined threshold. The predetermined threshold indicates a short circuit condition.Type: ApplicationFiled: December 21, 2007Publication date: June 2, 2011Applicant: MDL CorporationInventor: Raymond Kohler
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Patent number: 7948724Abstract: A bracket is provided for supporting a current transformer on a printed circuit board including a first aperture and a second aperture. The bracket includes a base portion including first and second ends, the base portion extending therebetween; a first mounting portion extending laterally from the first end of the base portion to an end of the first mounting portion, the first mounting portion being structured to be coupled with the first aperture in the printed circuit board; and a second mounting portion extending laterally from the second end of the base portion to an end of the second mounting portion, the second mounting portion being structured to be coupled with the second aperture in the printed circuit board. The end of the first mounting portion forms a first tab and the end of the second mounting portion forms a second tab, which are structured to extend through and be coupled with the first and second apertures, respectively.Type: GrantFiled: September 25, 2008Date of Patent: May 24, 2011Assignee: Eaton CorporationInventors: Bradley D. Colson, Luther L. Huey
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Patent number: 7936541Abstract: A fault interrupter and load break switch includes a trip assembly configured to automatically open a transformer circuit electrically coupled to stationary contacts of the switch upon the occurrence of a fault condition. The fault condition causes a Curie metal element electrically coupled to at least one of the stationary contacts to release a magnetic latch. The release causes a trip rotor of the trip assembly to rotate a rotor assembly. This rotation causes ends of a movable contact of the rotor assembly to electrically disengage the stationary contacts, thereby opening the circuit. The switch also includes a handle for manually opening and closing the electrical circuit in fault and non-fault conditions. Actuation of the handle coupled to the rotor assembly via a spring-loaded rotor causes the movable contact ends to selectively engage or disengage the stationary contacts.Type: GrantFiled: May 8, 2008Date of Patent: May 3, 2011Assignee: Cooper Technologies CompanyInventors: Nicholas Brusky, Kurt Lawrence Lindsey
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Publication number: 20110090606Abstract: A countermeasure for mitigating Electromagnetic Pulse E3 (EMP-E3) induced currents flowing through the neutral of a star-connected three-phase power transformer without compromising its neutral end insulation performance. It comprises an external neutral-grounding device; a first linear resistor (R10) is connected from the transformer neutral (N) to ground (G) sized to render said induced currents, for any given EMP-E3 severity, reduced and inconsequential to the equipment operation. Contingently, a second non-linear neutral-grounding resistor (R11) provides a shunting path-to-ground of substantially low resistance, as prevailing by virtue of its non-linearity under large power system fault currents; such a bypass functionality is formulated/designed according to IEEE/ANSI/NEMA recommended insulation coordination guidelines in order to sustain proper protective margins to the equipment neutral basic insulation levels (BIL/BSL).Type: ApplicationFiled: October 19, 2009Publication date: April 21, 2011Inventors: Vanessa Ramirez, Alberto Ramirez
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Publication number: 20110062797Abstract: The subject of the invention is a protection system for voltage transformers, finding application in the attenuation of ferroresonant states occurring in voltage transformers in high and medium voltage grids. The system according to the invention contains a ferroresonance detection circuit (3), connected to the terminals of the secondary winding of the voltage transformer (2) and in parallel with a damping circuit (4), containing a switching means (6) connected in series with a damping burden (7). The system according to the invention contains a control block (5) connected to the switching means (6), characterised by that the control block (5) contains a PWM (Pulse Width Modulation) generator.Type: ApplicationFiled: May 14, 2009Publication date: March 17, 2011Inventor: Wojciech Piasecki
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Patent number: 7899630Abstract: A metering device of a power substation and method are provided for operating on a secondary analog waveform output by a transformer assembly receiving a primary waveform. The method includes stepping down the secondary waveform and generating a corresponding output signal; operating on the corresponding output signal for generating a corresponding first digital signal having a value proportional to the corresponding output signal and within a first range; and operating on the corresponding output signal for generating a corresponding second digital signal having a value proportional to the corresponding output signal and within a second range. The method further includes processing the first digital signal and outputting a corresponding first output signal; processing the second digital signal and outputting a corresponding second output signal; processing the first and second output signals; and generating output corresponding to the processing of the first and second output signals.Type: GrantFiled: February 25, 2008Date of Patent: March 1, 2011Assignee: Electro Industries/Gauge TechInventor: Erran Kagan
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Patent number: 7859809Abstract: A test plug for use with protective relays has a circuit that when it detects an overvoltage on the secondary side of a current transformer limits the overvoltage amplitude and the occurrence of the overvoltage to a predetermined number of peaks that are less than all of the peaks that occur when the secondary side is open circuited and the test plug is connected to the relays. The test plug also ensures that there is a continuous flow of current in the relays. The test plug further that has an indicator visible external to the plug to indicate the occurrence of an open circuit transformer secondary and that indicator remains illuminated when the test plug is disconnected from the protective relays.Type: GrantFiled: September 12, 2008Date of Patent: December 28, 2010Assignee: ABB Technology AGInventors: Roy Ball, Russ Gonnam, Cristine Luong
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Patent number: 7813090Abstract: A DC switchgear is provided with a commutation-type DC circuit breaker having a main circuit provided with a main switch for interconnecting a DC power supply and a load, and a commutating circuit provided with a commutating capacitor and a commutating switch, which is connected electrically parallel to the main switch. The switchgear further has a DC circuit breaker accommodating box that includes the main circuit provided with the main switch, and the commutation-type DC circuit breaker; a front accommodating box disposed on the front of the DC circuit breaker accommodating box, which accommodates devices having functions for controlling the switchgear and indicating a status, such as a failure status thereof; and a rear accommodating box disposed on the back of the DC circuit breaker accommodating box. The front and rear accommodating boxes are connected to the DC circuit breaker accommodating box to form an integrated DC switchgear.Type: GrantFiled: January 24, 2008Date of Patent: October 12, 2010Assignee: Hitachi, Ltd.Inventors: Masato Suzuki, Yoshihiko Matsuda, Naoki Kawamura, Masaru Haga
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Patent number: 7755868Abstract: The electrical equipment comprises electrical elements corresponding to at least one phase of the distribution network and housed in a tank. The equipment is insulated with a dielectric liquid wherein the elements are immersed. The equipment comprises an input for each phase in the tank, and also a protection device, associated with at least one failure detector and configured so that, in the event of detecting such a failure, a short circuit will be established in the phases. The protection device is situated so as to establish the short circuit in a position before any protection, control or transformer element of the electrical equipment.Type: GrantFiled: January 5, 2007Date of Patent: July 13, 2010Inventor: Luis Gonzalo Flores Losada
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Publication number: 20100142102Abstract: A circuit breaker for a transformer includes means for interrupting circuitry in the transformer upon a fault condition in the transformer (the “fault interruption means”). The circuit breaker also includes means for interrupting the circuitry when a level of dielectric fluid in a tank of the transformer is unacceptably low (the “low oil trip means”). The fault interruption means includes a magnet, metal element, and first actuator. Upon the fault condition, the magnet and metal element separate, moving the first actuator to cause the electrical circuitry to open. The low oil trip means includes a float, insulating rod, and second actuator. When the dielectric fluid level drops to an unacceptably low level, the float and insulating rod drop, moving the second actuator to cause the circuitry to open. The low oil trip means operates independently of the fault interruption means, opening the circuitry without separating the magnet and metal element.Type: ApplicationFiled: December 3, 2009Publication date: June 10, 2010Applicant: Cooper Technologies CompanyInventor: Nicholas Paul Brusky
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PHASE-CONTROL SWITCHING APPARATUS AND SWITCHING CONTROL METHOD FOR PHASE-CONTROL SWITCHING APPARATUS
Publication number: 20100085668Abstract: A residual-magnetic-flux calculating unit includes a voltage-change-rate detecting unit that detects a transformer-voltage change rate from a phase voltage between a breaker and a transformer, a residual-magnetic-flux detecting unit that detects a residual magnetic flux remaining on the transformer based on the phase voltage, and a breaker-switching-state identifying unit that detects a switching state of the breaker. The residual-magnetic-flux calculating unit recalculates the residual magnetic flux based on the transformer-voltage change rate and a predetermined threshold while the breaker is in an open state.Type: ApplicationFiled: April 20, 2007Publication date: April 8, 2010Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Sadayuki Kinoshita, Kenji Kamei, Haruhiko Koyama, Tomohito Mori -
Patent number: 7640120Abstract: An arc detection means for detecting arcs in a plasma process includes at least one comparator to which an evaluation signal such as an output signal or an internal signal of an AC generator relating to the output signal and a reference value are supplied. The comparator is connected to a logic component that generates a signal for an arc suppression device.Type: GrantFiled: December 19, 2006Date of Patent: December 29, 2009Assignee: Huettinger Elektronik GmbH + Co. KGInventors: Sven Axenbeck, Markus Bannwarth, Martin Steuber, Peter Wiedemuth, Lothar Wolf
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Patent number: 7633737Abstract: A liquid immersed surge arrester that protects electrical equipment includes a module assembly. The module assembly includes at least one varistor and a pre-impregnated composite around the at least one varistor. The liquid immersed surge arrester also includes contacts on opposite ends of the module assembly with which the module assembly is connected to electrical equipment to be protected and to electrical ground. The liquid immersed surge arrester also includes a tank that houses the module assembly and the contacts. A fault-tolerant protection device for protecting electrical equipment includes a surge arrester to protect electrical equipment from damage during periods of voltage above a normal operating range. The fault-tolerant protection device also includes a surge durable fuse element to disconnect the surge arrester after failure of the surge arrester to allow unprotected operation of the electrical system.Type: GrantFiled: April 29, 2004Date of Patent: December 15, 2009Assignee: Cooper Technologies CompanyInventors: Michael M. Ramarge, Alan P. Yerges
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Patent number: 7629786Abstract: The invention is a harmonics reduction device for three-phase poly-wire power lines, which can more reliably eradiate harmonics current applied to an electric power system via a neutral line. The invention comprises an electric power system having three-phase poly-wire power lines in order to supply alternating-current (AC) power voltage to a load; a zigzag transformer in which windings connected with three-phase lines in the electric power system are wound through first and second legs, second and third legs, and third and first legs of a core having three legs, respectively, while varying direction of each magnetic flux, and an intermediate point of each winding is commonly connected with a neutral line of the electric power system and that of the load; and an open delta connection portion in which an winding connected with the neutral line of a load side is wound through the three legs so as to be connected with a neutral line of the electric power system.Type: GrantFiled: August 25, 2005Date of Patent: December 8, 2009Inventor: Sung Ho Lee
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Publication number: 20090279216Abstract: A fault interrupter and load break switch includes a trip assembly configured to automatically open a transformer circuit electrically coupled to stationary contacts of the switch upon the occurrence of a fault condition. The fault condition causes a Curie metal element electrically coupled to at least one of the stationary contacts to release a magnetic latch. The release causes a trip rotor of the trip assembly to rotate a rotor assembly. This rotation causes ends of a movable contact of the rotor assembly to electrically disengage the stationary contacts, thereby opening the circuit. The switch also includes a handle for manually opening and closing the electrical circuit in fault and non-fault conditions. Actuation of the handle coupled to the rotor assembly via a spring-loaded rotor causes the movable contact ends to selectively engage or disengage the stationary contacts.Type: ApplicationFiled: May 8, 2008Publication date: November 12, 2009Applicant: Cooper Technologies CompanyInventors: Nicholas Brusky, Kurt Lawrence Lindsey
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Patent number: 7589943Abstract: A device for reducing Geomagnetically-Induced Currents (GIC) in transformer apparatus of an AC power system that comprises a resistor (R10) in parallel with a protective varistor (V10) forming a passive-circuit arrangement. Such passive-circuit arrangement is connected on one end (N) to the neutral of the transformer and grounded on the other end (G). The combination of these elements produces a conductive path from said neutral to ground resulting in a proper reduction of said GIC currents, while substantially sustaining the neutral-grounding characteristics of said transformer.Type: GrantFiled: March 24, 2007Date of Patent: September 15, 2009Inventors: Vanessa de los Angeles Ramirez, Alberto Raul Ramirez
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Patent number: 7561387Abstract: A current transformer comprises a coil, a core and a shunt member. The core forms a magnetic circuit and has a first permeability. At least a portion of the core is encircled by the coil. The shunt member is coupled to the core and has a second permeability. The shunt member is continuous and forms a magnetically parallel path with the at least a portion of the core encircled by the coil. The current transformer may be incorporated in to a trip device.Type: GrantFiled: October 19, 2005Date of Patent: July 14, 2009Assignee: Eaton CorporationInventors: Theodore J. Miller, Joseph J. Matsko, Mark A. Juds
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Patent number: 7561396Abstract: Disclosed herein is an apparatus for connection to the secondary terminals of a CT to prevent CT damage and electric shock when the secondary terminals are opened, by providing an input signal and operating a relay circuit to short the CT secondary terminals. The apparatus monitors opening of the CT secondary terminals, and to prevent accidental opening, determines opening and provides an over voltage breaking upon opening. To prevent false operation of the protecting relay connected to the secondary terminals caused by the over voltage generated by accident other than opening of the CT secondary terminals, a secondary delay time of operation of the protecting relay is provided that can be variously set by DIP switch or otherwise, allowing the user to choose a desired setting. Further, expected over voltage values can be set according to load characteristics, allowing the apparatus to operate during voltage above the set value.Type: GrantFiled: March 9, 2005Date of Patent: July 14, 2009Assignee: Samsung Measuring Instruments Co., LTDInventor: Ki-Chan Song
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Patent number: 7558032Abstract: A protection system for a transformer system that includes three single phase transformers with auxiliary secondary windings, respectively. The auxiliary secondary windings are connected to form an open delta configuration. The protection system is connected into the open delta configuration, between the auxiliary secondary windings of two of the transformers. The protection system includes a circuit having an element with a threshold voltage and current characteristic connected in series with a thermal protection device and a resistor.Type: GrantFiled: July 8, 2004Date of Patent: July 7, 2009Assignee: ABB Research Ltd.Inventors: Wojciech Piasecki, Marek Florkowski, Mariusz Luto, Pentti Mahonen
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Patent number: 7525780Abstract: Disclosed is an inverter-circuit power supply circuit capable of redriving an inverter circuit upon temporary blackout without turning on a main power again An inverter-circuit power supply circuit according to the present invention cuts off a backlight driving signal from a microcomputer (11d2) with a Zener diode (18a), a first transistor (19a), and a second transistor (20a) when a power supply voltage from a main power supply circuit (12a) is lowered, by use of a power recovery circuit (12c3) to thereby cancel a protective function of a protective circuit (17).Type: GrantFiled: April 11, 2007Date of Patent: April 28, 2009Assignee: Funai Electric Co., Ltd.Inventor: Tsukasa Okamatsu
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Publication number: 20090097173Abstract: A control unit of an electric power supply system causes, responsive to a closing command signal, a switch corresponding to R phase to be thrown at a timing when a stationary magnetic flux and a residual magnetic flux of R phase are coincident with each other and then subsequently causes other switches corresponding to S phase and T phase to be thrown at a timing which is delayed from a zero point of an alternating voltage of R phase by a predetermined phase angle of 0-30 degrees, such that the difference of the stationary magnetic flux and the residual magnetic flux of each of S phase and T phase is minimum. Therefore, an exciting incoming current which flows into a three-phase transformer at a time of throwing a three-phase breaker provided with interpole capacitors can be suppressed.Type: ApplicationFiled: March 19, 2008Publication date: April 16, 2009Applicant: MITSUBISHI ELECTRIC CORPORATIONInventors: Sadayuki KINOSHITA, Kenji Kamei, Tomohito Mori, Hiroki Ito
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Publication number: 20090091867Abstract: A device is provided for monitoring through-fault current in an electric transformer on an electrical power system. The device generally includes a magnitude calculator for calculating the magnitude of current (e.g., a root means square value of current or magnitude of a fundamental of current) based on the current through the electric transformer. A through-fault energy calculator is further provided which is coupled to the magnitude calculator for calculating a through-fault energy value based on the magnitude of current or the calculated current through the transformer. An accumulator is coupled to the through-fault energy calculator for accumulating a plurality of through-fault energy values, and an alarm coupled to the accumulator for indicating that the accumulated through-fault energy values exceed a selected threshold.Type: ApplicationFiled: October 8, 2008Publication date: April 9, 2009Inventors: Armando Guzman-Casillas, Normann Fischer
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Publication number: 20090059447Abstract: A method and a device for fault detection in an n-winding, three-phase power transformer. For each of the windings (Wi) the three phase currents (IL1—Wi; IL2—Wi; IL3—Wi) are measured. For each of the windings (Wi) deciding if a zero sequence current (I0—Wi) reduction is to be performed depending on at least one user setting (kWi) and if so, deducting the zero sequence current (I0—Wi) from each of the three phase currents (IL1—Wi; IL2—Wi; IL3—Wi). For each of the windings (Wi) generating normalized currents by performing a magnitude compensation and a phase angle shift compensation on the results of the previous step. For each of the three phases (Lx) comparing the normalized current of a single winding with the normalized currents of all other windings. For each phase (Lx) generating a fault signal, if a difference between the single winding (W1) and all other windings (W2, . . . , Wn) exceeds a predefined level.Type: ApplicationFiled: August 24, 2006Publication date: March 5, 2009Applicant: ABB TECHNOLOGY LTDInventor: Zoran Gajic