A method can be used to determine a fault location in a power transmission line that connects a first terminal with a second terminal. Parameters associated with travelling waves are detected from measurements carried out at the first and second terminals. The parameters include arrival times of first and second peaks of the travelling waves at the first and second terminals respectively, and rise times of the first peaks of corresponding travelling waves. A first half, a second half, or a mid-point of the power transmission line is identified as having a fault based on the parameters. The fault location can be estimated based on the arrival times of the first and second peaks of the travelling waves detected from measurements carried out at the first and second terminals, a velocity of propagation of the travelling wave in the power transmission line, and/or a length of the power transmission 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.

The invention relates to a transient based method for identifying faults in an electric power transmission and/or distribution system (100) having at least one current transmission line (L.sub.12, L.sub.13, L.sub.23) comprising the following steps: —generation of a physical model of the at least one current transmission line (L.sub.12, L.sub.13, L.sub.23), the physical model depending on the fault parameters and describing the behavior of voltage and/or current transients due to the fault in the at least one current transmission line, fault parameters comprising a fault location parameter on said current transmission line (L.sub.12, L.sub.13, L.sub.23) and a fault impedance parameter, —measurement of voltage and/or currents evolution at least at one specific location in the said power system (100), —iterative simulation of the voltage and/or current evolution by the physical model at the measurement point with a set of fault parameters where at each step of iteration, simulated and measured voltage and/or current evolutions are compared and the set of fault parameters is adapted according to a convergence criterion, —identification of a fault with its fault parameters when convergence of the measured voltage and/or current evolutions and simulated voltage and/or current evolutions is reached in a limited number of iterations.

Protection of an electric power delivery system using a traveling wave overcurrent element is disclosed herein. A maximum traveling wave mode among the alpha and beta modes is selected and compared with a traveling wave overcurrent threshold to determine a traveling wave overcurrent. Traveling wave overcurrent protection may be enabled depending on a termination status of the protected electric power delivery system. When a remote terminal is terminated on high surge impedance, a local protection system may use local traveling wave current quantities to determine a traveling wave overcurrent, and the traveling wave overcurrent may be used for line protection. Systems for detecting a termination status use local and remote current quantities.

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.

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.

Protection of an electric power delivery system using a traveling wave overcurrent element is disclosed herein. A maximum traveling wave mode among the alpha and beta modes is selected and compared with a traveling wave overcurrent threshold to determine a traveling wave overcurrent. Traveling wave overcurrent protection may be enabled depending on a termination status of the protected electric power delivery system. When a remote terminal is terminated on high surge impedance, a local protection system may use local traveling wave current quantities to determine a traveling wave overcurrent, and the traveling wave overcurrent may be used for line protection. Systems for detecting a termination status use local and remote current quantities.

The technology described herein is generally directed towards a system for power transmission system protection and fault location, such as implemented in a deployable device at one or more junction points of a power transmission system. Aspects of the described technology can be directed to analyzing a traveling wave corresponding to a fault on a power transmission system. Example aspects can comprise receiving data representing current and voltage components of a traveling wave, maintaining the data in storage for fault location determination of the fault, transforming the data via a wavelet transform, into wavelet transform results and using the wavelet transform results for protection of the power transmission system.

A method for fault location to single-terminal traveling wave includes steps as follows. Step (a): recording a waveform of a traveling wave signal of disturbance by a traveling wave device when a line disturbance occurs. Step (b): performing a phase mode transformation on the waveform recorded by the step (a), so as to obtain components of line mode and zero mode of a fault initial traveling wave, and performing a wavelet transform to decompose the components of the line mode to obtain singularities in the waveform of the traveling wave. Step (c): calculating a wavefront slope k of the components of the line mode of the fault initial traveling wave. Step (d): computing a preliminary fault distance D according to the slope k computed in the step (c). Step (e): confirming a fault point according to the preliminary fault distance and wavelet singularities of the components of the line mode. Step (f): end.