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7579843 |
Methods and apparatus for analyzing partial discharge in electrical machinery
Methods and apparatus for analyzing electrical insulation of an electrical machine are provided. The method includes receiving a first signal that includes a plurality of partial discharge pulses...
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7330033 |
Noncontact sensor
A noncontact voltage sensor is housed in a container comprising a container body having an opening on one side and an insulation cover body for sealing the opening. A plate type electrode insulated...
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7292048 |
Method and apparatus for measuring a dielectric response of an electrical insulating system
Method and device for measuring a dielectric response of an electrical insulating system, wherein a first measurement result is determined by a frequency domain method and a second measurement...
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7279905 |
Method and an apparatus for supervising the operation of current transformers
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...
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7227367 |
Current transformer test device and method
A current transformer test method implemented using a test device, is useful to verify proper CT installation and operation, and does not rely on the generator (or other system) to be in a state of...
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7196884 |
Apparatus and method for detecting the loss of a current transformer connection coupling a current differential relay to an element of a power system
Disclosed is an apparatus and method for detecting a loss of a current transformer connection coupling a protective relay to a power system element of a three-phase power system and providing a...
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7174261 |
Power line sensors and systems incorporating same
An apparatus for sensing the current in a power line of a power system and systems incorporating the apparatus are disclosed. The apparatus may comprise an enclosure providing a window operable to...
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7167007 |
Apparatus and method for field testing MOV arresters
Embodiments test MOV arresters. One embodiment comprises applying a plurality of voltages to a high voltage lead of the MOV arrester, the plurality of voltages being changed between an initial test...
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7161873 |
Method of detecting and locating a source of partial discharge in an electrical apparatus
A method of detecting and localizing a source of partial discharge in an electrical apparatus placed in an enclosure containing an acoustically-conductive fluid. The method consists in:
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7148679 |
Transformer probe
A probe ( 10 ) for sensing movement of a body of magnetic material comprises a magnetically energisable pole piece ( 30 ), a closed loop electrical circuit ( 20 ) having a first end ( 25 ) which is...
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7119548 |
Current transformer test device and method
A current transformer test device and a method implemented using the test device, is useful to verify proper CT installation and operation, and does not rely on the generator (or other system) to...
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7107186 |
Transformer testing
A method for transformer testing includes receiving a failing test result of a transformer, the test result being determined from a test taken during transformer manufacture, determining, via a...
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7106078 |
Method and apparatus for measuring transformer winding resistance
The present invention is a method of and an apparatus for measuring resistances of at least one transformer winding ( 109 ) in configurations of connected transformers windings. The method is based...
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7102360 |
Procedure to measure grounding resistances of electrical installations by measuring the loop impedance
A procedure to measure the grounding resistances of electrical installations by measuring the loop impedance. According to this procedure, using voltage generator transformers, a current is...
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7081757 |
Re-locatable partial discharge transducer head
An apparatus ( 10 ) for detecting the occurrence of partial discharge in electrical equipment, such as high voltage transformers. The apparatus comprises a detecting means including an ultrasonic...
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7071701 |
Online fiber optic sensor for detecting partial discharge and similar events in large utility station transformers and the like
An approved method and apparatus for detecting partial discharge events within a transformer comprises asserting a MEMS acoustical probe through the wall of the transformer to optically measure...
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7034547 |
Method of diagnosing a fault on a transformer winding
The present invention relates to a method of diagnosing a fault on a transformer winding by using frequency response analysis. The method comprises the steps of: measuring the impedance on said...
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7030602 |
Testing of current transformers
A method for evaluating the accuracy of a current transformer is presented. The current transformer has a primary winding and a secondary winding. A current is not circulated through the primary...
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6990415 |
Evaluation circuit for a current sensor using the compensation principle, in particular for measuring direct and alternating currents, and a method for operating such a current sensor
A current sensor using the compensation principle, in particular for measuring direct and alternating currents, includes an entirely digital evaluation circuit for signal processing. This...
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6987390 |
Method for testing a transformer and corresponding test device
Testing a transformer by applying to the transformer a test signal, the frequency of which may be lower than the nominal frequency of the transformer. The voltage of the test signal may also be...
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6954060 |
a-c current transformer functional with a d-c current component present
The magnetic core of an a-c current transformer is optimized so that the current transformer is able to function with a primary electric current having a d-c current component. In the preferred...
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6949934 |
Fault-annuciating system for a transformer
A preferred embodiment of a transformer includes a core, and a primary and a secondary winding positioned on the core so that the primary and secondary windings are inductively coupled when the...
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6930610 |
Monitoring system and method for wiring systems
A monitoring system includes at least one partial discharge (PD) sensor. The PD sensor is configured to monitor a component of an aircraft wiring system and to acquire a monitoring signal. A method...
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6812713 |
Internal fault indicator for power electrical devices
An internal fault indicator for an electrical device is triggered by a sudden increase in pressure as occurs when an insulation failure creates an electric arc. The heat released in the arc is...
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6809525 |
Method and system for estimating conductor losses in a transformer
A preferred method for estimating conductor losses in a transformer having a first and a second winding includes energizing the first winding while the second winding is short-circuited by an...
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6807495 |
Plausibility checking of voltage transformers in substations
The invention relates to a method, a computer program product, a computer program and a device ( 20 ) for the plausibility checking of voltage transformers ( 8 ) in an electrical switchgear ( 1 )...
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6788077 |
Automated test sequence editor and engine for transformer testing
A system and method for creating, editing, and/or executing a test program for testing a transformer is provided. The system includes an input that allows the user to select the desired test...
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6774639 |
Partial discharge monitoring system for transformers
An apparatus for detecting partial discharge in on-line high voltage electrical equipment containing a dielectric, such as high voltage transformers. The apparatus includes an ultrasonic transducer...
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6753686 |
Method and apparatus for detecting failure of differential transformer, and method and apparatus for signal processing of differential transformer
An offset signal for failure detection, that cannot be removed if an input signal line is broken is applied from an offset application circuit with output impedance higher than impedance of a...
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6714022 |
Apparatus and method for cooling power transformers
The load current drawn from a power transformer is sensed to determine if and when the load current exceeds a predetermined threshold. The length of time the load current exceeds the threshold is...
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6680616 |
In-service testing of current transformers
A system and method for testing an on-line current transformer is provided. The current transformer includes a primary winding and a secondary winding. An operating current continues to flow...
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6661238 |
Abnormality diagnosis method and apparatus for separable transformer
A diagnosis apparatus ( 20 ) mounted to a separable transformer includes an arithmetic control section ( 27 ) for inputting, through a differential amplifier ( 24 ), a signal smoothing circuit 25 ...
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6633168 |
Method and apparatus for detecting partial discharge in a voltage transformer
A method and apparatus for detecting a partial discharge in a voltage transformer, the transformer having a first voltage winding and a second voltage winding. A grounded electrostatic shield being...
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6580276 |
Tap switch for frequency response and partial discharge measurement
A system and method for conducting diagnostic services on live electrical equipment, such as electrical power transformers using a tap switch installed into each phase of the transformer. The tap...
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6580783 |
2nd level power fault testing apparatus for testing telecommunications equipment
A power fault testing apparatus for testing telecommunications equipment interfaces to Telcordia's 2 nd Level AC power fault standards. The apparatus is powered by a three-phase 480 VAC, 600 A...
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6566895 |
Unbalanced three phase delta power measurement apparatus and method
An apparatus and method are used to determine equivalent individual phase voltages and phase currents from an alternating delta power source and load configuration. A delta-wye input transformer...
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6563296 |
Closely-coupled multiple-winding magnetic induction-type sensor
The invention relates to sensors for detecting a time-varying current by employing a plurality of coils with separate windings, disposed on separate toroidal cores, that are placed in close...
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6549017 |
System and method for on-line impulse frequency response analysis
The on-line winding test unit determines a characteristic signature of a monitored winding(s) in a transformer, generator, or the like. A sensor detects incoming pulses, originating elsewhere on...
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6545479 |
Portable tester for electronic circuit breaker
A portable circuit breaker tester ( 10 ) for testing a current transformer ( 30, 32, 34, 36 ) of a circuit breaker ( 18 ) having a first terminal ( 30 e , 32 e ) on a first end of the transformer...
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6535000 |
Method and apparatus for determining the internal impedance of a distribution transformer and sensing DC current through an AC power meter
A method for determining the DC current flowing through an AC power meter. The internal impedance of the distribution transformer is first sensed, then the DC voltage in the AC voltage waveform is...
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6518771 |
Method of monitoring the contact burnoff in tap changers
A method of monitoring contact burnoff in tap changers operating under load in which the load current is measured and for nominal variation of the voltage of the particular tap parameters are...
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6492819 |
High voltage switch and switching process for impulse measurement
A switching assembly for performing impulse measurement testing on each of a plurality of transformer terminals includes a first plurality of single pole, double throw switches and a switch...
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6466034 |
Transformer winding movement detection by high frequency internal response analysis
Transformer winding movement is detected by providing an input sensor inside the transformer on an input winding lead and providing an output sensor inside the transformer on an output winding...
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6420879 |
System and method for measurement of partial discharge signals in high voltage apparatus
A system is disclosed for monitoring electrical partial discharge signals in electrical power apparatus. The apparatus includes a housing and a plurality of openings in the housing through which...
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6392419 |
Apparatus for and method of monitoring the status of the insulation on the wire in a winding
An apparatus for monitoring the status of the insulation on the wire in a winding in a device comprises a surrogate sample of insulating material having a thickness and properties selected to fail...
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6369582 |
System and method for off-line impulse frequency response analysis test
The winding testing unit provides a system and method for determining a characteristic signature of a winding residing in a device, such as a transformer or generator. A pulse/signal generator...
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6340890 |
Method and device for locating partial discharges in an electric high-voltage apparatus
A method and apparatus for location of partial discharges in an electric high-voltage apparatus, such as a power transformer, which is arranged in a container filled with an insulating medium is...
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6323655 |
Method and device for detecting partial discharges
A method and device for detecting partial discharges in an electrical apparatus placed in a tank filled with oil, wherein the tank wall is provided with at least one drain tap. The device includes...
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6313642 |
Apparatus and method for testing an arcing fault detection system
A system for testing an arcing fault detection system in an electrical distribution network having a line conductor carrying an electrical signal between a power source and a load, the arcing fault...
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6313640 |
System and method for diagnosing and measuring partial discharge
A method and system diagnose and measure partial discharge on-line in a power transmission system. A first wideband directional clamp-on detector detects pulses corresponding to partial discharge...
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