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Match Document Document Title
9008982 Systems and methods for determining residual flux in a power transformer  
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...
8861155 High-impedance fault detection and isolation system  
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...
8823356 Supply voltage auto-sensing  
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...
8433528 Ground fault detection system and method  
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...
8421475 AC current sensor for measuring electric AC current in a conductor and an indicator system comprising such a sensor  
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...
8415777 Integrated circuit with millimeter wave and inductive coupling and methods for use therewith  
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...
8217536 Magnetizing inrush current suppression device for transformer and control method of same  
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...
8054014 Control system for an electrical machine  
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...
7812615 Method and device for fault detection in transformers or power lines  
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...
7786735 Corrective device protection  
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...
7732940 Apparatus and method for reducing neutral line current using load switching method  
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...
7616005 Corrective device protection  
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...
7466113 Break-before-make sensing for drivers  
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....
7319576 Apparatus and method for providing differential protection for a phase angle regulating transformer in a power system  
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...
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...
7196886 Reverse wiring detect in circuit interrupting devices  
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...
7106565 Directional ground relay system  
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...
6833711 Protective relay for powers systems having dependable out-of-step blocking capability  
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...
6785105 Ground fault detection system for ungrounded power systems  
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...
6720749 Three-phase motor protector apparatus  
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...
6671151 Network protector relay and method of controlling a circuit breaker employing two trip characteristics  
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...
6573726 Sensitive ground fault detection system for use in compensated electric power distribution networks  
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...
6504693 Network protector relay providing a close function  
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...
6493203 Phase control switch apparatus  
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...
6392858 Electronic trip device with phase reconstitution and a circuit breaker comprising such a trip device  
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...
6175810 Method of generating a signal identifying a three-pole short-circuit occuring in a three-phase power transmission line  
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...
6154687 Modified cosine filters  
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...
6147616 Automatic power interruption and re-supply relay for an electric power line  
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...
6114859 Harmonic characteristic measuring method and harmonic characteristic measuring apparatus  
Single-phase currents at two frequencies fα and fβ (fα
6104106 Solid state circuit breaker  
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...
6064001 High current electrical switching apparatus with poles interleaved and modules joined by interference fit of joining block in undercut grooves in molded casings  
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...
5883796 Dynamic series voltage restoration for sensitive loads in unbalanced power systems  
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...
5883578 Loss of potential determination for use in protective relays for electric power systems  
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...
5859530 Process for determining the phase sequence in a three-phase network (rotary current network)  
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...
5822165 Sequence based network protector relay with forward overcurrent protection and antipumping feature  
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,...
5784240 Method and apparatus for limiting current surge upon transfer of a load between A.C. power sources  
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...
5777835 Third phase reconstruction from a two current transformer sensor with three-phase true RMS and phase loss determination capabilities  
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...
5768079 Adaptive ground and phase fault detection for a power distribution system  
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...
5751132 Electric motor monitoring circuit  
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...
5710542 Method of measuring the A.C. current in a conductor in an A.C. power transmission network  
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...
5659453 Arc burst pattern analysis fault detection system  
A method and apparatus are provided for detecting an arcing fault on a power line carrying a load current. Parameters indicative of power flow and possible fault events on the line, such as...
5642003 Power system switch incorporating a positive-sequence fundamental signal magnitude detector  
A power switching apparatus includes a positive-sequence fundamental signal magnitude detector. The positive-sequence fundamental signal magnitude detector derives a positive-sequence fundamental...
5570257 Phase sequence wiring protection apparatus  
A phase sequence protection circuit is shown in which first and second resistors (R1, R2) and a first capacitor (C1) all having equivalent impedance are connected in a Y configuration and coupled...
5570258 Phase monitor and protection apparatus  
A phase monitor and protection circuit is shown in which an impedance network (21, 23, 25) in a respective branch (20, 22, 24) connected to a neutral (26) is coupled to each phase of a three phase...
5548207 Missing phase detector  
A missing phase detector circuit which monitors the ac three-phase output voltages of power equipment or sources and produces an output signal in the event a missing ac phase is detected. The...
5528134 AC power analyzer  
A harmonic analyzer using a short sampling window eliminates truncation artifacts in the sampling of an AC power waveform by equating the length of the sample period to a period of the sampled...
RE35260 Voltage rotation indicator mounting apparatus  
A voltage rotation indicator for testing the phase sequence of live multi-phase electrical power is mounted within a housing. The housing is provided with structure for removably mounting the...
5475559 Negative-sequence time-overcurrent relay  
Disclosed is a negative-sequence time-overcurrent relay for use in a polyphase synchronous rotary electric machine having a main-circuit breaker and an exciting circuit. The negative-sequence...
5420503 Phase sequence indicator  
A phase sequence indicator with two measuring contacts for contacting with connections of the object to be measured has a grouring contact touchable by the user, an evaluation circuit connected to...
5406437 Zero phase sequence current filter with adjustable impedance  
The invention provides a zero phase sequence current zig-zag filter with adjustable zero phase sequence impedance and a method for adjusting the impedance of the filter. Impedance is adjusted in...

Matches 1 - 50 out of 177 1 2 3 4 >