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Document Title |
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7599161 |
Relay device and corresponding method
A method of operating a relay device, in an electrical circuit comprising first and second main circuit breakers, and a bus tie circuit breaker connecting the first and second main circuit...
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7542256 |
Relay device and corresponding method
A method of operating a relay device, the method comprising the steps of: providing main circuit-breakers and a bus-tie-breaker connecting the main-circuit-breakers; defining a...
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7535233 |
Traveling wave based relay protection
An apparatus includes at least one Rogowski coil and a processor. The at least one Rogowski coil is positioned within an electrical power distribution network to detect a first traveling wave...
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7472026 |
Multi-ended fault location system
A system and method for locating faults on multi-terminal power system transmission lines uses synchronized phasor measurements to accurately determine fault location and fault impedance regardless...
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7457088 |
Systems and methods for protection of electrical networks
A system and method for accomplishing power swing blocking and unstable power swing tripping schemes during disturbances of electrical networks is disclosed. The disclosed system and method...
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7345863 |
Apparatus and method for identifying a loss of a current transformer signal in a power system
Provided is an apparatus and method for identifying a specific lost current transformer (CT) signal of number of CT signals provided by a corresponding number of CTs coupling a protective device to...
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7345862 |
Protective relay for power systems having fault distance measurement filter logic
The system is used in a distance-type protective relay which includes a calculation circuit responsive to voltage and current values from a power line to produce a quantity which is analogous to...
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7299143 |
Method and apparatus for improving operational reliability during a loss of a phase voltage
The present invention is directed to a method and apparatus for improving operational reliability during a loss of a phase voltage (LOV) in a multi-phase power system, wherein a voltage...
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7233470 |
Distance relay apparatus
A distance relay apparatus includes a directional relay element which performs computation to detect a fault, which occurs in the forward direction from an installing point of the relay apparatus,...
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7199989 |
Digital protection relay with time sync function
In a digital protection relay with a time sync function, the sampling timing of which is specified based on a reference timing transmitted from a time signal generator to a time sync unit, with a...
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7085938 |
Protective relay with embedded web server
A protective relay having an embedded web server to allow communication with a remote device having a standard web browser package. The relay can receive and transmit HTML files according to the...
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7050913 |
Method and apparatus for monitoring power quality in an electric power distribution system
A composite power quality indication generated from user weighted statistical contributions of selected system parameters provides an overall indication of power quality in an electric power...
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6989977 |
Digital directional relay
A digital directional relay converts a voltage value and a current value of a power system into digital voltage data and digital current data by periodic sampling and determines a direction of a...
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6944554 |
Method for detecting fault on transmission lines by using harmonics and state transition diagram
Disclosed is a method for detecting a fault by using harmonics and a state transition diagram. When the fault occurs on transmission lines, the fault is detected by using harmonics and the state...
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6924647 |
Fault location method and device
The present invention relates to a method for calculating the distance to fault in a section of a power transmission network, which section is arranged with line terminals at both ends, each...
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6879917 |
Double-ended distance-to-fault location system using time-synchronized positive-or negative-sequence quantities
When a disturbance (for example, lightning strike) occurs on a high-voltage overhead transmission line, the line must be checked for any possible damage. If the distance-to-fault is known, line...
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6873508 |
Protective relay system
In a protective relay system according to an aspect of the present invention, a direction of a fault is correctly determined during system oscillation using one of a negative-phase-sequence relay...
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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...
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6829544 |
Line current differential protective relaying method and relay for in-zone tapped transformers
A line current differential protective relay and method for protecting transmission lines with power transformers tapped between the substations without any measurements taken at the tap point. The...
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6760670 |
Crossover fault classification for power lines with parallel circuits
The invention describes a method, system, device, and computer-readable medium having computer-executable instructions for classifying faults on an electrical power line. In particular, the...
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6661630 |
Distance relay for protection of transmission line having minimized reactance effect
A distance relay for protection of a transmission line, which is capable of estimating apparent impedances with respect to faults on the transmission line involving fault resistances, more...
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6633166 |
Method for generating an error signal identifying a short circuit
The invention is directed to a method for producing a fault signal indicating a short-circuit between a first phase conductor and a second phase conductor of two different, parallel-running,...
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6498709 |
Digital distance relay
A digital distance relay for deciding whether a fault point is within a stipulated operation region by obtaining an impedance to the fault point. The relay comprises: means for deciding whether the...
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6483435 |
Method and device of fault location for distribution networks
The present invention relates to a method for location of a fault which has occurred on one of a plurality of lines in a power distribution network where the location is performed with the measured...
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6469629 |
Distributed logic in multiple protective relays
A protective relay, system, and relay operation method which allows logic functions to be distributed amongst multiple protective relays associated with a power distribution system. The protective...
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6459960 |
Distance relay equipment
A short-circuit distance relay has a short-circuit distance relay element that calculates a fault impedance from voltage and current which are introduced from a power system and that compares the...
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6426856 |
Method for monitoring a protective gear
A method of operating a protective gear is described, in particular a remote protective gear for an electric power grid. In this method, a voltage signal is derived from the line voltage, and a...
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6397155 |
Method and apparatus for automatically controlled gain switching of monitors
A method and apparatus for automatically controlling gain switching of a monitor. To automatically control gain switching, an electronic circuit splits an input channel into a plurality of gain...
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6392857 |
Device and process for protecting a line of a network of electricity supply lines
This device for protecting a line ( 10, 12 ) of a network of supply lines comprises two protective relays ( 18, 20; 22, 24 ) furnished with means for detecting faults and a circuit breaker adapted...
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6385022 |
Method and apparatus for deriving power system data from configurable source points
A protective relay that derives and processes power system data from multiple user-configurable data source points. Data from multiple source points can be combined in the relay as a single source...
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6369996 |
Fault protection scheme
A method of protecting a section of a line is disclosed. The method comprises providing a local fault protection assembly at one end of the section distal from at least one remote fault protection...
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6336059 |
Reach-measurement method for distance relays and fault locators on series-compensated transmission lines using local information
A reach-measurement method is used in connection with a series-compensated line of a power system. The series-compensated line includes an installed series capacitance having a bus side and a line...
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6324557 |
Combination exerciser gripper and calculator
A combination exercise gripper and calculator includes an electronic calculator, with a keypad, a power source, a visual display means, such as a liquid crystal display, and a calculating computing...
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6307723 |
Parallel-feeder directional overcurrent protection
When directional overcurrent protection relays are included at the load end of a set of parallel feeders fed from an AC power source, a minimum fault-current threshold is specified based on the...
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6239959 |
Ground distance relay for AC power transmission line protection
An improved reactance characteristic for an overall ground distance quadrilateral characteristic embodies a particular phase selector, possibly among a plurality of phase selectors and variables,...
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6222711 |
Bus-bar protection relay equipment
A bus-bar protection relay equipment includes a data-acquisition means, a check zone protection means, a fault bus-bar judging means, and a tripping bus-bar judging means. A data-acquisition means...
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6173216 |
Protective relay with improved, sub-window cosine filter
As a variation of the non-orthogonal filter, a phasor estimate is computed by using an N-point window. An aspect of the sub-window cosine filter is to repeat the basic cosine filter for only...
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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...
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6137666 |
High speed, selective protective relays
A protective relay receives current and voltage inputs, digitizes them and reduces the effects of high and low frequency noise. In the case of a distance relay, incorporated in the relay is a...
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6046895 |
Distance protection method
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6028754 |
System for preventing undesired protective relay tripping actions due to coupling capacitor voltage transformer transients
The system impedance ratio (SIR) is determined for the original zone 1 distance element reach of a protective relay. The reduction in the original zone 1 reach is then determined, using the SIR...
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5956220 |
Adaptive distance protection system
An adaptive distance relaying system provides improved performance for parallel circuit distance protection. The system utilizes the parallel circuit's current, when available, in conjunction with...
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5878375 |
Data transfer switching device and method of use therefore
A data switch for transferring data from either actual line readings or from stored memory to the input of a relay tester. The device uses a digital switch set between the A/D converter and the CPU...
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5839093 |
System for locating faults and estimating fault resistance in distribution networks with tapped loads
Both fault location and fault resistance of a fault are calculated by the present method and system. The method and system takes into account the effects of fault resistance and load flow, thereby...
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5838525 |
High speed single-pole trip logic for use in protective relaying
A protective relaying system includes a local protective relay operatively coupled to a protected line segment at a first location, and a remote protective relay operatively coupled to the...
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5798932 |
Methods and apparatus for removing error due to decaying offsets from measured power system currents
A digital decaying current offset correction method and apparatus, in one aspect, separates the requirements of detecting fault existence from the requirements of detecting fault location. Once the...
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5796258 |
Adaptive quadrilateral characteristic distance relay
A quadrilateral characteristic relay system for determining a fault associated with a multiple-phase electric power transmission system is disclosed. The system dynamically adapts one line of the...
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5793595 |
Multi-application relay for power systems
A microprocessor-based multifunction overcurrent relay for protecting power systems has a plurality of overcurrent elements implemented in a software program. Sufficient overcurrent elements are...
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5790418 |
Adaptive polarizing memory voltage time constant
At least two different time constants are used to produce the polarizing memory reference voltage which in turn is used in a protective relay for power transmission lines. For most conditions, a...
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5783946 |
Fault type classification algorithm
A process for identifying the type of fault detected by a protective relay includes measuring pre-fault and post-fault samples of current waveforms on the phase-A, phase-B and phase-C conductors of...
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