Patent application number | Description | Published |
20080281540 | APPARATUS AND METHOD FOR ESTIMATING SYNCHRONIZED PHASORS AT PREDETERMINED TIMES REFERENCED TO A COMMON TIME STANDARD IN AN ELECTRICAL SYSTEM - An apparatus and method estimates a plurality of synchronized phasors at predetermined times referenced to an absolute time standard in an electrical power system. The method includes acquiring and determining a frequency of a power system signal, sampling the power system signal at a sampling interval rate based on a frequency of the power system signal to form signal samples, and generating a plurality of acquisition time values based on an occurrence of each of the signal samples at a corresponding plurality of different times referenced to the absolute time standard. The method further includes adjusting a phasor of each of the signal samples based on a time difference between a corresponding selected acquisition time value and a predetermined time referenced to an absolute time standard to form the plurality of synchronized phasors. | 11-13-2008 |
20090088989 | SYMMETRICAL COMPONENT AMPLITUDE AND PHASE COMPARATORS FOR LINE PROTECTION USING TIME STAMPED DATA - A set of current measurements may be transmitted from a remote Intelligent Electronic Device (IED) to a local IED. The current measurements may comprise a timestamp and/or be associated with timestamp information to allow the local IED to time align the local current measurement with the remote current measurement. The local IED may detect a fault within the power system segment defined by the local and remote IEDs by comparing an operating current to a scaled restraint current. A fault may also be detected by comparing the operating current to a scaled nominal current. The operating and restraint currents may be derived from the local and remote current measurements. The restraint current scale may be derived from the characteristics of the local and/or remote IED. The current measurements may correspond to a negative-sequence component and/or a zero-sequence component of a three-phase current measurement set. | 04-02-2009 |
20090088990 | SYNCHRONIZED PHASOR PROCESSOR FOR A POWER SYSTEM - A device is provided for monitoring and controlling various power system device and elements. The device generally includes a communications channel for receiving phasor data associated with a location on the power system. The device further includes a logic engine which performs scalar, vector and/or other complex calculation based on the phasor data to provide control data or an output signal for effecting the various other power system devices or elements to provide local or wide area protection, control, and monitoring to maintain power system stability. | 04-02-2009 |
20090089608 | SYSTEMS AND METHODS FOR POWER SWING AND OUT-OF-STEP DETECTION USING TIME STAMPED DATA - A first intelligent electric device (IED) may be placed at a first location in an electrical power system and a second IED may be placed at a second location in the electrical power system. Voltage measurements may be received from the first and second IEDs. The measurements may be time aligned and used to calculate an angle difference between the first location and the second location in the electrical power system. A slip frequency and acceleration may be derived from the angle difference. The angle difference, slip frequency, and acceleration may be used to detect an out-of-step (OOS) condition in the electrical power system and/or a power swing between the first location and the second location in the electrical power system. The angle difference, slip frequency, and acceleration may also be used to predicatively detect OOS conditions. | 04-02-2009 |
20090091867 | Transformer Through-Fault Current Monitor - 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. | 04-09-2009 |
20090099798 | Real-Time Power System Oscillation Detection Using Modal Analysis - A power system oscillation detection device is provided for use in an electric power system. A plurality of sample signals are acquired from the electrical power system via a plurality of intelligent electronic devices (IEDs) in communication with the power system. The power system oscillation detection device includes a real-time modal analysis module, a real-time mode identification module, and real-time decision and control logic. The real-time modal analysis module calculates modes of at least one of the signals, each mode including mode information. The real-time mode identification module together with the real-time decision and control logic determines, from the mode information, whether there is an undesirable oscillation in the electric power system and activates a remedial action. | 04-16-2009 |
20090125158 | STATE AND TOPOLOGY PROCESSOR - A State and Topology Processor (STP) may be communicatively coupled to one or more intelligent electronic devices (IEDs) communicatively coupled to a electrical power system to obtain one or more current measurements, voltage measurements, and dynamic topology data therefrom. The STP may receive the measurement data and may determine a current topology and a voltage topology therefrom. A current processor may use the current topology and the current measurements to refine the measurements, perform KCL, unbalance, symmetrical component, and consistency checks on the electrical power system. The voltage processor may use the voltage topology and the voltage measurements to perform similar checks on the electrical power system. One or more alarms may be generated responsive to the checks. The data may be displayed to a user in a display of a human machine interface and/or may be transmitted to a user programmable task module, and/or an external control unit. | 05-14-2009 |
20100002348 | DISTRIBUTED BUS DIFFERENTIAL PROTECTION USING TIME-STAMPED DATA - A distributed busbar protection system using time-stamped data gathered from measurement devices in an electrical power system bus arrangement by respective intelligent electronic devices (IEDs). The IEDs may derive the timestamp information from a clock or other time source, which may be synchronized to a common time source and/or an absolute time. The time-stamped measurement data may be used by a protection device to monitor and/or protect the electrical power system. The protection device may include a real-time vector processor, which may time-align the time-stamped data, determine one or more bus differential protection zones, and implement a differential protection function within each of the protection zones. One or more protective control signals may be transmitted to the IEDs to trip the corresponding breakers and clear the bus fault. | 01-07-2010 |
20100125373 | MINIMIZING CIRCULATING CURRENT USING TIME-ALIGNED DATA - A power system may comprise two or more transformers operating in parallel. A voltage differential may exist between the transformers, which may create a circulating current in the power system. The system voltage of the power system may be modified by performing a tap change operation on one or more of the transformers. The tap change operation may be configured to minimize the circulating current. The circulating current may be minimized by determining the bias between the transformers using an angular difference between the transformer currents. The angular difference may be calculated using time-aligned measurement data. A tap change operation configured to modify the system voltage, while minimizing circulating current, may be determined using the transformer bias. | 05-20-2010 |
20100264749 | DIFFERENTIAL ELEMENT WITH HARMONIC BLOCKING AND HARMONIC RESTRAINT OPERATING IN PARALLEL - An intelligent electronic device (IED) provides harmonic blocking and harmonic restraint differential protection operating in parallel. The IED includes a harmonically-blocked differential element supervised by one or more even harmonics of a raw operating current (a current comprising the fundamental operating current and the harmonics thereof). The IED also includes a parallel, harmonically-restrained differential element, which is restrained by harmonics of the raw operating current. Tripping signals output by the parallel harmonically-blocked differential element and the harmonically-restrained differential element may be selectively combined into a single tripping signal output. An additional harmonic blocking element may supervise both differential elements and/or the combined tripping signal. The additional harmonic blocking element may provide odd-harmonic blocking, such as harmonic blocking based on a fifth harmonic of the raw operating current. | 10-21-2010 |
20100286838 | ISLANDING DETECTION IN AN ELECTRICAL POWER DELIVERY SYSTEM - An intelligent electronic device is operable to use a signal derived from an electrical power delivery system to effectively detect an islanding condition. The intelligent electronic device is configured to compare a frequency deviation (from nominal frequency) and a rate-of-change of frequency of the electrical power delivery system to a protection characteristic of the intelligent electronic device to quickly and securely detect islanding conditions thereby enhancing power protection, automation, control, and monitoring performance. The intelligent electronic device uses local measurements of the electrical power deliver system to provide reliable and economical means to properly separate a generation site from the remainder of the electrical power delivery system. Such may be useful to prevent reclosing out of synchronism. | 11-11-2010 |
20110004425 | STATE AND TOPOLOGY PROCESSOR - A State and Topology Processor (STP) may be communicatively coupled to one or more intelligent electronic devices (IEDs) communicatively coupled to a electrical power system to obtain one or more current measurements, voltage measurements, and dynamic topology data therefrom. The STP may receive the measurement data and may determine a current topology and a voltage topology therefrom. A current processor may use the current topology and the current measurements to refine the measurements, perform KCL, unbalance, symmetrical component, and consistency checks on the electrical power system. The voltage processor may use the voltage topology and the voltage measurements to perform similar checks on the electrical power system. One or more alarms may be generated responsive to the checks. The data may be displayed to a user in a display of a human machine interface and/or may be transmitted to a user programmable task module, and/or an external control unit. | 01-06-2011 |
20110068803 | ELECTRICAL POWER SYSTEM PHASE AND GROUND PROTECTION USING AN ADAPTIVE QUADRILATERAL CHARACTERISTICS - A quadrilateral distance module may be used to detect faults in an electrical power system. A resistive coverage of the quadrilateral distance module may be defined by an adaptive resistance blinder. The adaptive resistance blinder may be adapted to certain power system conditions, such as forward load flow and/or reverse load flow. A forward adaptive resistance blinder may be calculated in parallel with a reverse adaptive resistance blinder. The forward adaptive resistance blinder may use a polarizing quantity adapted for forward load flow conditions, and the reverse adaptive resistance blinder may use a polarizing quantity adapted for reverse load flow conditions. Fault detection may comprise comparing both the forward and reverse adaptive resistance blinders to power system stimulus and detecting a fault when the stimulus satisfy either blinder. | 03-24-2011 |
20110077885 | APPARATUS AND METHOD FOR ESTIMATING SYNCHRONIZED PHASORS AT PREDETERMINED TIMES REFERENCED TO A COMMON TIME STANDARD IN AN ELECTRICAL SYSTEM - An apparatus and method estimates a plurality of synchronized phasors at predetermined times referenced to a common time standard in an electrical power system. The method includes acquiring and determining a frequency of a power system signal, sampling the power system signal at a sampling interval rate based on a frequency of the power system signal to form signal samples, and generating a plurality of acquisition time values based on an occurrence of each of the signal samples at a corresponding plurality of different times referenced to the common time standard. The method further includes adjusting a phasor of each of the signal samples based on a time difference between a corresponding selected acquisition time value and a predetermined time referenced to a common time standard to form the plurality of synchronized phasors. | 03-31-2011 |
20110264388 | FAULT LOCATION IN ELECTRIC POWER DELIVERY SYSTEMS - Accurately calculating location of a fault even on a branched, non-homogenous, radial electric power distribution system. The calculation includes determining a calculated reactance or impedance to the fault, and uses the line parameters to determine locations on the system that match the calculated reactance to the fault. The calculation may further include a determination of faulted phase and eliminate fault location possibilities based on absence of the faulted phase at those locations. The calculation may further use data reported from line monitors such as faulted circuit indicators (FCIs). | 10-27-2011 |
20110264389 | Fault Location in Electric Power Delivery Systems - Accurately calculating location of a phase-to-phase fault even on a branched, non-homogenous, radial electric power distribution system. The calculation includes determining a calculated reactance to the fault without using positive-sequence current measurements, and uses the line parameters to determine locations on the system that match the calculated reactance to the fault. The calculation may further include a determination of faulted phase and eliminate fault location possibilities based on absence of the faulted phase at those locations. | 10-27-2011 |
20120068717 | FAULT LOCATION IN A NON-HOMOGENEOUS ELECTRIC POWER LINE - Fault location on a non-homogeneous electric power line that includes a plurality of sections by determining a section in which negative-sequence voltage magnitude profiles calculated from each terminal of the power line intersect. The fault location may determine the faulted section and determine the location of the fault within the faulted section. To determine the fault location, the negative-sequence voltage magnitude profiles may be calculated from measurements taken at each terminal of the power line and compared to determine a point where the profiles intersect. The profiles may be calculated using power line properties and measurements from each terminal. | 03-22-2012 |
20130096854 | Fault Location Using Traveling Waves - Disclosed herein are various embodiments of systems and methods for calculating a fault location in electric power delivery system based on a traveling wave created by an electrical fault in the electric power delivery system. According to one embodiment, an intelligent electronic device may be configured to detect a transient traveling wave caused by an electrical fault. A first traveling wave value of the transient traveling wave may be determined and a corresponding first time associated with the first traveling wave may be determined. The IED may receive a second time associated with a second traveling wave value of the transient traveling wave detected by a remote IED. The distance to the remote IED may be known. An estimated fault location may be generated based on the time difference between the first time and the second time. Additional methods of calculating the fault location may also be employed. | 04-18-2013 |
20140074414 | Fault Location Using Traveling Waves - Disclosed herein are various embodiments of systems and methods for calculating a fault location in electric power delivery system based on a traveling wave created by an electrical fault in the electric power delivery system. According to one embodiment, an intelligent electronic device may be configured to detect a transient traveling wave caused by an electrical fault. A first traveling wave value of the transient traveling wave may be determined and a corresponding first time associated with the first traveling wave may be determined. The IED may receive a second time associated with a second traveling wave value of the transient traveling wave detected by a remote IED. The distance to the remote IED may be known. An estimated fault location may be generated based on the time difference between the first time and the second time. Additional methods of calculating the fault location may also be employed. | 03-13-2014 |
20140236502 | Electrical Power System Phase and Ground Protection Using an Adaptive Quadrilateral Characteristic - A quadrilateral distance module may be used to detect faults in an electrical power system. A resistive coverage of the quadrilateral distance module may be defined by an adaptive resistance blinder. The adaptive resistance blinder may be adapted to certain power system conditions, such as forward load flow and/or reverse load flow. A forward adaptive resistance blinder may be calculated in parallel with a reverse adaptive resistance blinder. The forward adaptive resistance blinder may use a polarizing quantity adapted for forward load flow conditions, and the reverse adaptive resistance blinder may use a polarizing quantity adapted for reverse load flow conditions. Fault detection may be performed by comparing both the forward and reverse adaptive resistance blinders to power system stimulus and detecting a fault when the stimulus satisfy either blinder. | 08-21-2014 |
20140351572 | Automatically Configurable Intelligent Electronic Device - Disclosed herein are intelligent electronic devices configured for monitoring an electric power delivery system and for determining a plurality of configuration settings based on measurements from the electric power delivery system. An IED may identify a configuration event, obtain a plurality of electrical parameters associated with the configuration event, determine a plurality of configuration parameters from the electrical parameters, determine a plurality of configuration settings based on the configuration parameters, and apply the settings to the IED. The IED may also be configured to initiate the configuration event by opening a single pole of a multi-phase power line. | 11-27-2014 |
20150081234 | POWER LINE PARAMETER ADJUSTMENT AND FAULT LOCATION USING TRAVELING WAVES - Fault location using traveling waves in an electric power delivery system according to the embodiments herein uses line parameters that are adjusted using traveling wave reflections from known discontinuities in the electric power delivery system. The arrival times of a traveling wave and a reflection of the traveling wave from a known discontinuity may be used to adjust parameters of the electric power delivery system such as, for example, line length. The adjusted parameter can then be used to more accurately calculate the location of the fault using the traveling waves. | 03-19-2015 |
20150081235 | FAULT LOCATION USING TRAVELING WAVES BY CALCULATING TRAVELING WAVE ARRIVAL TIME - A location of a fault in an electric power delivery system may be detected using traveling waves instigated by the fault. The time of arrival of the traveling wave may be calculated using the peak of the traveling wave. To determine the time of arrival of the peak of the traveling wave, estimates may be made of the time of arrival, and a parabola may be fit to filtered measurements before and after the estimated peak. The maximum of the parabola may be the time of arrival of the traveling wave. Dispersion of the traveling wave may also be corrected using an initial location of the fault and a known rate of dispersion of the electric power delivery system. Time stamps may be corrected using the calculated dispersion of the traveling wave. | 03-19-2015 |
20150081236 | TRAVELING WAVE VALIDATION USING ESTIMATED FAULT LOCATION - Electric power delivery system fault location systems and methods as disclosed herein include validation of the received traveling wave fault measurements. Validation may include estimating a location of the fault using an impedance-based fault location calculation. Time windows of expected arrival times of traveling waves based on the estimated fault location and known parameters of the line may then be established. Arrival times of traveling waves may then be compared against the time windows. If the traveling waves arrive within a time window, then the traveling waves may be used to calculate the location of the fault. | 03-19-2015 |