A power-distribution system can detect a transmission-line electrical fault, and the power source can be electrically isolated from the transmission line before a human or equipment is substantially harmed or damaged. A controller on the source side is responsive to one or more sensors that provide a signal indicative of the voltage across the transmitter side of the transmission line. A source-disconnect device operable by the controller electrically isolates the source from the transmission line. A signal-generator circuit is configured to superimpose a higher-wavelength carrier waveform with the source-output waveform on the transmission line. The controller determines the normal impedance of the transmission line from measurement and detects a transmission-line fault, as indicated by a change in carrier waveform reflections or energy content of the carrier waveform and generates a command to open the source-disconnect device upon detection of the fault.

A testing apparatus for imposing a traveling wave signal on an electric system signal for testing a fault detector is disclosed herein. The fault detector may be configured to simulate a fault at a particular location by controlling the timing of the traveling wave signal. The testing apparatus may be configured to impose multiple traveling wave signals to test the accuracy of the fault location determined by the fault detector. The testing apparatus may be configured to determine the calculation accuracy of the fault detector. The testing apparatus may impose a traveling wave signal on a signal simulating an electrical signal on an electric power delivery system. The testing apparatus may be used to test capabilities of a fault detector of detecting a fault using traveling waves or incremental quantities.

A bipolar DC power transmission scheme including first and second DC poles, each including a respective DC power transmission medium extending between first and second ends; a plurality of converters wherein each end of the transmission medium of each of the poles is operatively connected to at least one of the converters to form a rectifier and an inverter at opposite ends of the DC power transmission media; and a controller to operate at least one converter of one of the rectifier and inverter in a control mode and at least one converter of the other of the rectifier and inverter in a second control mode in response to a fault occurring on either of the poles. Additionally, the first control mode decreases and the second control mode increases the operating DC voltage of the or each corresponding converter from a normal operating voltage value.

The present disclosure pertains to systems and methods for obtaining and processing high-frequency electric power system measurements for control and monitoring of an electric power system. High-frequency measurements may be used to detect traveling waves and/or to detect faults in the electric power system. In various embodiments, a processing device may receive high-frequency electric power system measurements from each of a local location and a remote location and may process the high-frequency electric power system measurements to identify and locate a fault. The occurrence of and location of a fault and may be used to implement protective actions to remediate identified faults.

A testing apparatus for imposing a traveling wave signal on an electric system signal for testing a fault detector is disclosed herein. The fault detector may be configured to simulate a fault at a particular location by controlling the timing of the traveling wave signal. The testing apparatus may be configured to impose multiple traveling wave signals to test the accuracy of the fault location determined by the fault detector. The testing apparatus may be configured to determine the calculation accuracy of the fault detector. The testing apparatus may impose a traveling wave signal on a signal simulating an electrical signal on an electric power delivery system. The testing apparatus may be used to test capabilities of a fault detector of detecting a fault using traveling waves or incremental quantities.

The present disclosure pertains to systems and methods for supervising protective elements in electric power systems. In one embodiment, a system may be configured to selectively enable a protective action an electric power system. The system may include a data acquisition subsystem receive a plurality of representations of electrical conditions associated with at least a portion of the electric power delivery system. An incremental quantities module may calculate incremental quantities from the plurality of representations. The system may be configured to detect an event, to determine an incremental quantities value during the event, and to determine a time-varying threshold. The incremental quantities value during the event may be compared with the time-varying threshold, and a protective action module may be enabled to implement a protective action when the value of the incremental quantities value during the event exceeds the time-varying threshold.

A method and system is provided for locating a fault in a mixed power transmission line. The method is implemented by an Intelligent Electronic Device (IED) of the mixed line. The IED detects a travelling wave from one or more signals received from one or more measurement equipment. Thereafter, the IED identifies a line section with the fault, and generates two or more estimates for the location of the fault based on a time difference between arrival of two peaks of the travelling wave, a velocity of propagation of the travelling wave in the line section identified with the fault, and a length of one or more line sections. The IED determines the location of the fault based on a comparison of each estimate with a threshold, wherein the threshold is estimated based on the one or more signals, equivalent source impedance of each source and total line impedance.

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.

A system for monitoring the state of a cable, includes a plurality of transferometry devices capable of injecting a test signal into the cable and measuring a signal being propagated in the cable, the transferometry devices being positioned along the cable so as to break down the cable into successive sections, the system comprising a control member capable of communicating with the transferometry devices and configured so as to perform at least one transferometry test consisting in injecting a test signal into the cable by means of a first transferometry device and measuring the test signal after its propagation in the cable by means of a second transferometry device different from the first device, the system comprising a post-processing member capable of communicating with the transferometry devices and configured to compare the measured signal to a reference signal to deduce therefrom an indicator of degradation of the section of cable disposed between the first transferometry device and the second transferometry device.

A system for locating defects on a single-wire earth-return (SWER) network can include a network, a plurality of data collection units, and a server communicably coupled to the plurality of data collection units via the network. Each data collection unit can be positioned at a distribution transformer of the SWER network and configured to measure broadband signals originating from a defect along the SWER network; convert the broadband signals to a digital signal; extract parameters from the digital signal; and transmit the extracted parameters over the network. The server can be configured to receive the extracted parameters from each of the plurality of data collection units; and determine a location of the defect based on the extracted parameters.