The invention relates to protection from faults in a power transmission system having two or more transmission lines. Travelling waves are detected from a signal obtained with a measurement equipment associated with a bus of the power transmission system. Arrival times of a first peak of a first travelling wave, a second travelling wave and a third travelling wave, are detected from the signal. A value for line length is calculated from the arrival times and propagation velocity of the travelling wave in the corresponding transmission line. The calculated value is compared with an actual length of the corresponding transmission line, for determining if the fault is an internal fault or an external fault. According to the fault being one of the internal fault and the external fault, a signal for controlling a switching device associated with the corresponding transmission line is generated.

A system for monitoring the state of a cable, includes a plurality of reflectometry devices able to inject a test signal at a point of injection into the cable and to measure a signal having propagated back through the cable to the point of injection into the cable, the reflectometry devices being intended to be positioned along the cable so as to divide the cable into successive segments, the system comprising a control unit that is able to communicate with the reflectometry devices and that is configured so as to carry out at least one reflectometry test consisting in injecting a test signal into the cable by means of a first reflectometry device and measuring the test signal, by means of the first reflectometry device, after it has propagated through the cable and been reflected from an impedance discontinuity, the system further comprising a post-processing unit able to communicate with the reflectometry devices and configured to analyze the measurement of the test signal with a view to detecting an amplitude peak corresponding to a fault.

The present disclosure pertains to systems and methods for detecting lightning and using such information to implement appropriate control strategies in an electric power system. In one embodiment, a system may include a data acquisition subsystem configured to receive a plurality of representations of electrical conditions associated with at least a portion of the electric power system. The system may also include a traveling wave subsystem to identify an initial traveling wave in the electric power system and generated by lightning and identify at least one subsequent traveling wave in the electric power system and generated by lightning. A lightning analysis subsystem may perform an analysis of the initial traveling wave and the at least one subsequent traveling wave to determine a characteristic of the ionosphere based on the analysis and a lightning location. An adaptive control subsystem may adjust a control strategy based on the lightning location.

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.

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. A protective module 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.

Phase selection for traveling wave fault detection systems is disclosed herein. Intelligent electronic devices (IEDs) may be used to monitor and protect electric power delivery systems by detecting and acting upon traveling waves. A phase of the electric power delivery system may be selected based on the relative polarity of the traveling waves detected. The amplitude and/or polarity of the selected phase may be compared with the amplitudes and/or polarities of the other phases to determine a fault condition. For instance, the IED may determine a single-phase-to-ground fault based on the relative polarities and magnitudes of the detected traveling waves, send a protective action to the identified faulted phase, and/or continue to monitor the system for a continuation of the event or identification of a different event, such as a three-phase fault, using incremental quantities.

A method identifies a location of a fault on a faulty line of an electrical power supply network having a plurality of lines, a plurality of inner nodes, and at least three outer nodes. The outer nodes each bound a line and are provided with measurement devices which are used to measure high-frequency current and/or voltage signals. To locate faults, one of the outer nodes is selected as the starting node for the search for the fault location. Starting from the starting node, paths to the other outer nodes are determined, and that those paths on which the fault location could be located are selected. A line on which the fault location could be located, in principle, is identified for each of the selected paths using the respective times at which the traveling waves arrive, and a potential fault location is determined for the respectively identified line.

The present invention related to the field of power system protection and control, presents a voltage travelling wave differential protection method considering the influence of frequency-dependent parameters, which provides more accurate and rapid fault identification. The technical scheme of the present invention is as follows: a calculation method of voltage travelling-wave differential protection for VSC-HVDC transmission lines, taking the influence of the frequency-dependent parameters into consideration, the steps are as follows: calculating a characteristic impedance and propagation coefficient of the frequency-dependent transmission line in time domain, collecting voltage and current signals at the both ends of the transmission line and then calculating the forward and backward voltage travelling wave, respectively, comparing a differential value of voltage travelling wave with a preset threshold value to determine whether the internal fault occurs. The present invention is mainly applied in the field of power system protection and control.

Systems and methods may mitigate risk of fire caused by an electric power system. In one embodiment, a system may include an intelligent electronic device (IED). The IED includes a communication subsystem to receive a signal from a sensor related to a condition of the electric conductor. A processing subsystem in communication with the communication subsystem may operate in at least two modes comprising a high security mode and a fire prevention mode. In the fire prevention mode, the IED may interrupt a flow of electric current based on the signal from the at least one sensor associated with the electric conductor. In the high security mode, the system may interrupt a flow of electric current based on the signal from the at least one sensor associated with the electric conductor and based on a second condition relating to the electric conductor.

The invention relates to protection from faults in a power transmission system having two or more transmission lines. Travelling waves are detected from a signal obtained with a measurement equipment associated with a bus of the power transmission system. Arrival times of a first peak of a first travelling wave, a second travelling wave and a third travelling wave, are detected from the signal. A value for line length is calculated from the arrival times and propagation velocity of the travelling wave in the corresponding transmission line. The calculated value is compared with an actual length of the corresponding transmission line, for determining if the fault is an internal fault or an external fault. According to the fault being one of the internal fault and the external fault, a signal for controlling a switching device associated with the corresponding transmission line is generated.