Abstract: Fault classification and zone identification in a power transmission system are described. Voltage or current measurements are obtained at a terminal of the transmission line in each of the three phases measured during a fault. Modal transformations are performed on voltage or current measurements to obtain traveling wave signals with reference to each of the three phases. Based on the magnitude of the traveling wave signals the fault is classified.

Abstract: Examples of fault location in a power transmission line connecting a first and a second terminal is described. In an example, arrival times of a first peak, a second peak, and a third peak of a travelling wave detected from measurements carried out at the first and second terminals is detected. A rise time associated with the first peak of the travelling wave is calculated. One of a first half and a second half of the power transmission line is identified, as having a fault, based on a comparison of the rise time. One of a first segment, a second segment, a third segment, and a fourth segment of the power transmission line is identified as having the fault. Length of the power transmission line is estimated. The fault location is estimated based on identification of one of the first, second, third, and fourth segments as having the fault.

Abstract: Techniques for distance protection of a transmission line include determining a fault inception time from a voltage and/or current, determining rate of change sample values indicative of a rate of change of the voltage and/or of a rate of change of the current for at least one sample time that is dependent on the fault inception time, and using the rate of change sample values to generate a phase classifier for fault classification of a zone classifier for faulted zone identification.

Abstract: Examples of fault location in a power transmission line connecting a first and a second terminal is described. In an example, arrival times of a first peak, a second peak, and a third peak of a travelling wave detected from measurements carried out at the first and second terminals is detected. A rise time associated with the first peak of the travelling wave is calculated. One of a first half and a second half of the power transmission line is identified, as having a fault, based on a comparison of the rise time. One of a first segment, a second segment, a third segment, and a fourth segment of the power transmission line is identified as having the fault. Length of the power transmission line is estimated. The fault location is estimated based on identification of one of the first, second, third, and fourth segments as having the fault.

Abstract: Fault location determination in a power transmission system is described. Samples of voltage and current measured are obtained for each phase at a terminal. A first equivalent reactance value based on the samples of voltage and current is calculated. Further, based on the calculated equivalent reactance value a first fault location is determined.

Abstract: Examples for protecting a power transmission line in response to a fault occurring within a monitored zone in a power transmission system are described. In an example, an occurrence of the fault in at least one phase of the power transmission line may be identified. Thereafter, an actual rate of change of incremental current is calculated based on calculated incremental currents. With the actual rate of change determined, a threshold for rate of change of incremental current is calculated based on calculated incremental voltages, the calculated incremental currents, line parameters, and a zone setting for the monitored zone. Based on comparison of the actual rate of change and the threshold for the rate of change, the fault is determined to have occurred in the monitored zone. Thereafter, a trip signal may be generated for controlling a switching device associated with the power transmission line.

Abstract: Examples of fault location in a power transmission line connecting a first and a second terminal is described. In an example, arrival times of a first peak, a second peak, and a third peak of a travelling wave detected from measurements carried out at the first and second terminals is detected. A rise time associated with the first peak of the travelling wave is calculated. One of a first half and a second half of the power transmission line is identified, as having a fault, based on a comparison of the rise time. One of a first segment, a second segment, a third segment, and a fourth segment of the power transmission line is identified as having the fault. Length of the power transmission line is estimated. The fault location is estimated based on identification of one of the first, second, third, and fourth segments as having the fault.

Abstract: A device is provided that is suitable for use with a double-circuit power transmission system having a first line and a second line. The device comprises an interface to receive a current measurement for the second line. The device comprises at least one processing module operative to estimate a first zero-sequence current in the first line based on a second zero-sequence current, and determine an apparent impedance based on the estimated first zero-sequence current.

Abstract: A method and device can be used with a power transmission line. Pre-fault voltage and current phasors and during-fault voltage and current phasors for each of first, second, and third terminals are determined based on disturbance records. Using an assumed faulted section, values for a propagation constant of each section, a surge impedance of each section, and a fault location parameter are computed. The computing is based on simultaneously solving pre-fault and during-fault objective functions for the assumed faulted section with the computed pre-fault and during-fault voltage and current phasors. The pre-fault and during-fault objective functions are formulated based on equating junction voltages determined from two of the terminals, conservation of charge at the junction, and equating fault location voltages determined from one terminal and the junction. The values determined for the propagation constant, the surge impedance, and the fault location parameter can be compared with predefined criteria.

Abstract: A device can be used with a power transmission system that includes three section that are connected at a junction, each section being from a corresponding. An input interface receives measurements of voltages and currents carried out at one or more of the first terminal, the second terminal and the third terminal or positive sequence voltage and current phasors obtained from the measurements of voltages and currents carried out at one or more of the first terminal, the second terminal and the third terminal. A phasor calculation module calculates positive sequence voltage and current phasors from the measurements of voltages and currents carried out at a terminal of the power transmission system. A fault locator obtains the fault location based on the section with the fault, the positive sequence voltage and current phasors obtained for each terminal, and the positive sequence line impedance parameters of each section.

Abstract: Techniques for identifying faulty sections in power transmission lines are described. A first positive sequence voltage and first positive sequence current at a first terminal of a power transmission line are computed based on a first voltage and first current at the first terminal. A second positive sequence voltage and second positive sequence current at a second terminal are computed based on a second voltage and second current. Based on the first positive sequence voltage and the first positive sequence current, a first junction voltage and first junction current from the first terminal at a junction are computed. Based on the second positive sequence voltage and the second positive sequence current, a second junction voltage and second junction current from the second terminal are computed. A ratio of a junction voltage parameter to a junction current parameter is computed. Using the ratio, the faulty section is identified.

Abstract: The invention provides an Intelligent Electronic Device (IED) and a method for locating a fault in a power transmission line with the IED. The method comprises measuring arrival times of a first, second and third peak of a travelling wave, using measurements obtained with one or more measurement equipment connected with the power transmission line. The method further comprises generating two or more initial estimates for the location of the fault, estimating time of initiation of the travelling wave, and estimating an arrival time of the third peak. The estimated arrival time of the third peak is compared with the measured arrival time of the third peak, to select an initial estimate of the two or more initial estimates as the location of the fault.

Abstract: The invention provides a method and device for fault section identification in a multi-terminal mixed line. The method comprises obtaining positive sequence voltage and current phasors from measurements of voltages and currents at each terminal of the mixed line. The method further comprises calculating a voltage phasor for each terminal, wherein the calculation of the voltage phasor for a first terminal is performed using at least the voltage and current phasors obtained for one of a second terminal and a third terminal, and the current phasor obtained for the first terminal. Thereafter, the method comprises determining a section of the mixed line having the fault, based on comparison of the calculated and obtained voltage phasors for each terminal. In addition, the method comprises controlling a switching device with a re-trip signal generated based on the determination of the section with the fault.

Abstract: A system can be used for analyzing fault data in a power transmission network with a plurality of power transmission lines. A number of power system devices are distributed across the power transmission network. Each power system device performs one or more of measurement of data to generate measured data and processing of the measured data to generate processed data in response to a condition in a corresponding segment of the power transmission network. The system includes a data aggregator, a data analyzer, and a fault locator.

Abstract: A method of protection can be used in response to a fault in a multi-terminal power transmission system that includes a first transmission line section connecting a first terminal to a transmission line junction, a second transmission line section connecting a second terminal to the transmission line junction and a third transmission line section connecting a third terminal to the transmission line junction. The fault being located in one of the first, second or third transmission line sections. The section having the fault can be determined based on a number of calculations and other factors and a switching device can be controlled according to the identification of the section having the fault.

Abstract: A device can be used with a power transmission system that includes three section that are connected at a junction, each section being from a corresponding. An input interface receives measurements of voltages and currents carried out at one or more of the first terminal, the second terminal and the third terminal or positive sequence voltage and current phasors obtained from the measurements of voltages and currents carried out at one or more of the first terminal, the second terminal and the third terminal. A phasor calculation module calculates positive sequence voltage and current phasors from the measurements of voltages and currents carried out at a terminal of the power transmission system. A fault locator obtains the fault location based on the section with the fault, the positive sequence voltage and current phasors obtained for each terminal, and the positive sequence line impedance parameters of each section.

Abstract: The invention provides a method and device for fault section identification in a multi-terminal mixed line. The method comprises obtaining positive sequence voltage and current phasors from measurements of voltages and currents at each terminal of the mixed line. The method further comprises calculating a voltage phasor for each terminal, wherein the calculation of the voltage phasor for a first terminal is performed using at least the voltage and current phasors obtained for one of a second terminal and a third terminal, and the current phasor obtained for the first terminal. Thereafter, the method comprises determining a section of the mixed line having the fault, based on comparison of the calculated and obtained voltage phasors for each terminal. In addition, the method comprises controlling a switching device with a re-trip signal generated based on the determination of the section with the fault.

Abstract: A method and device can be used with a power transmission line. Pre-fault voltage and current phasors and during-fault voltage and current phasors for each of first, second, and third terminals are determined based on disturbance records. Using an assumed faulted section, values for a propagation constant of each section, a surge impedance of each section, and a fault location parameter are computed. The computing is based on simultaneously solving pre-fault and during-fault objective functions for the assumed faulted section with the computed pre-fault and during-fault voltage and current phasors. The pre-fault and during-fault objective functions are formulated based on equating junction voltages determined from two of the terminals, conservation of charge at the junction, and equating fault location voltages determined from one terminal and the junction. The values determined for the propagation constant, the surge impedance, and the fault location parameter can be compared with predefined criteria.

Abstract: Techniques for identifying faulty sections in power transmission lines are described. A first positive sequence voltage and first positive sequence current at a first terminal of a power transmission line are computed based on a first voltage and first current at the first terminal. A second positive sequence voltage and second positive sequence current at a second terminal are computed based on a second voltage and second current. Based on the first positive sequence voltage and the first positive sequence current, a first junction voltage and first junction current from the first terminal at a junction are computed. Based on the second positive sequence voltage and the second positive sequence current, a second junction voltage and second junction current from the second terminal are computed. A ratio of a junction voltage parameter to a junction current parameter is computed. Using the ratio, the faulty section is identified.

Abstract: The invention provides an Intelligent Electronic Device (IED) and a method for locating a fault in a power transmission line with the IED. The method comprises measuring arrival times of a first, second and third peak of a travelling wave, using measurements obtained with one or more measurement equipment connected with the power transmission line. The method further comprises generating two or more initial estimates for the location of the fault, estimating time of initiation of the travelling wave, and estimating an arrival time of the third peak. The estimated arrival time of the third peak is compared with the measured arrival time of the third peak, to select an initial estimate of the two or more initial estimates as the location of the fault.