Abstract: The present invention relates to estimating source impedances across one or more transmission lines connecting at least two substations. Each substation is associated with an equivalent source having a respective source impedance. Voltage and current measurements and status signals are obtained. The voltage and current measurements provide terminal or bus voltages and line currents at each terminal, and the status signals are associated with switching events at the one or more transmission lines or at the substations. An event associated with a disturbance or current injection is detected from one or more of the obtained measurements and the obtained status signals. The source impedance of each equivalent source is estimated based on the event, using line parameters and the voltage and current measurements associated with the event.

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: The present disclosure relates to a method for controlling a distance protection system, as well as a respective device and system for performing the method. Measurements are received. The measurements comprise current and/or voltage measurements at a first position along a transmission line for an electrical power system. A first impedance is computed from the received measurements. A fault location is determined from the computed first impedance and a first impedance boundary. Responsive to the determined fault location, a second impedance is computed. The fault location is redetermined from the computed second impedance and the first impedance boundary. The distance protection system is controlled based on the determined fault location or the re-determined fault location.

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: The present invention relates to estimating source impedances across one or more transmission lines connecting at least two substations. Each substation is associated with an equivalent source having a respective source impedance. Voltage and current measurements and status signals are obtained. The voltage and current measurements provide terminal or bus voltages and line currents at each terminal, and the status signals are associated with switching events at the one or more transmission lines or at the substations. An event associated with a disturbance or current injection is detected from one or more of the obtained measurements and the obtained status signals. The source impedance of each equivalent source is estimated based on the event, using line parameters and the voltage and current measurements associated with the event.

Abstract: The present subject matter describes fault detection during power swing in a power transmission system. Voltage and current measurements are obtained for each phase at a terminal of the power transmission system. Based on measurements obtained, a value of change in an impedance angle for each phase-to-ground loop and each phase-to-phase loop for each sampled value of voltage and current is calculated, where the value of change in the impedance angle is a difference between impedance angles of two samples separated by a predetermined interval. Further, the average values for change in impedance angle based on a predetermined number of values of the change in the impedance angle for each phase-to-ground loop and each phase-to-phase loop is calculated. The average values calculated are compared with a threshold of change in impedance angle and based on the comparison a fault in one or more of the phase-to-ground loops or phase-to-phase loops is detected and classified.

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 device or system for use with an electric power system is provided. The electric power system has a first bus, a second bus, a third bus, a first line between the first and second buses, and a second line between the third bus and one of the first and second buses. The device or system is operative to determine, responsive to at least one trip event, one or several updated impedances of an equivalent model across a line.

Abstract: The present invention relates to estimating source impedances across one or more transmission lines connecting at least two substations. Each substation is associated with an equivalent source having a respective source impedance. Voltage and current measurements and status signals are obtained. The voltage and current measurements provide terminal or bus voltages and line currents at each terminal, and the status signals are associated with switching events at the one or more transmission lines or at the substations. An event associated with a disturbance or current injection is detected from one or more of the obtained measurements and the obtained status signals. The source impedance of each equivalent source is estimated based on the event, using line parameters and the voltage and current measurements associated with the event.