Fault Location Method For Transmission Lines Research Articles

Research on New Energy Transmission Line Fault Localization Method Based on APSVMD-NTEO

Abstract Given the new energy transmission line fault, traveling wave head detection difficulties, wave speed uncertainty, positioning errors, and other problems, this paper proposes a new Teager energy operator based on adaptive parameter selection variational mode decomposition (APSVMD) and new energy transmission line fault location method (NTEO). The envelope fuzzy entropy is introduced to select the key parameters of SVM, and the sampling range of the Teager energy operator (TEO) is improved to effectively improve the capture accuracy of the wave head. In terms of fault location, by improving the double-ended traveling wave method, the uncertainty of wave speed and the effect of actual line length error is eliminated, and the ranging error is reduced.

New energy transmission line fault location method based on Pearson correlation coefficient

The access of new energy power source makes the traditional transmission line structure become complex, and due to the influence of power electronic device control strategy, the fault characteristics have been fundamentally changed, resulting in the traditional transmission line fault localization method can not be applied to the new energy sending line. To address the above problems, this paper analyzes the transient current characteristics of different power supply faults, and learns that there are obvious differences in the transient currents on both sides of the fault point inside and outside the transmission line area, and then proposes a new energy transmission line fault localization method based on the Pearson correlation coefficient, which determines the fault location by calculating the correlation coefficients of the fault waveforms of the neighboring monitoring points. Finally, comparative experiments are carried out under different fault types and fault locations to further verify the applicability of the proposed method.

Adaptive Fault Locator for High-Voltage Transmission Lines Based on the Estimation of Power System Model Parameters

Abstract This paper presents an adaptive transmission line fault location method, which incorporates fault location devices at both line ends and utilises data import from a supervisory control and data acquisition system without strictly requiring data synchronisation. The developed method aims at achieving a higher degree of robustness, adaptiveness and accuracy. The adaptiveness is achieved by dynamic updating of mathematical models used on the basis of network-wide information, such as data on the state of circuit-breakers and apparent power at load and generation nodes. The robustness and accuracy are enhanced by incorporating two stages of identification of model parameters with the goal of reducing the decision variable space for the stage identifying fault parameters. Furthermore, in addition to utilisation of all measurements available at a particular substation, the developed method partially employs the measurements from the other end of the line by means of result cross-checks, but does not require a full data set, unlike deterministic-model-based methods. An optimisation-based approach, redundancy on the basis of extended measurement set, and cross-checks reduce the risk of fault location errors due to measurement errors or “voids” in the data available. Testing of the developed method demonstrates its accuracy and robustness in a wide range of pre-fault and fault regime scenarios, even when considering various pre-fault contingencies.

An improved natural frequency based transmission line fault location method with full utilization of frequency spectrum information

An improved natural frequency based method is proposed to accurately locate faults in transmission lines. The method only requires three phase instantaneous current measurements at the local terminal of the line and is compatible with protective relays using high-speed tripping techniques. First, the theoretical peak frequencies along the entire frequency spectrum of the measured currents are derived, for different fault types, locations and resistances. Next, the fault location is determined by finding the minimum average distance between the theoretical and the measured peak frequencies. Compared to the existing natural frequency based fault location methods, the proposed method solves the mode mixing problem during single phase to ground faults and systematically considers the effect of fault resistances. In addition, the proposed method fully utilizes the frequency spectrum information instead of only the dominant frequency, and therefore overcomes the difficulty to extract the dominant frequency. Numerical experiments have shown that, compared to the existing method, the proposed method presents much higher fault location accuracy during single phase to ground faults, and slightly higher (comparable) fault location accuracy for other types of faults, regardless of fault locations and fault resistances.

A new method of single terminal traveling wave location based on characteristic of superposition of forward traveling wave and backward traveling wave

This paper proposed a novel one-terminal traveling -wave-based fault-location method for transmission lines. Traveling waves (TWs) are induced in transmission lines by the occurrence of a fault. Different are formed by the superposition of forward and backward TWs when a fault occurs. The proposed fault-location method used a fault-location function to determine the location of faults from corresponding TW change-points. The proposed fault-location method was evaluated through modeling and simulating a three-phase 500 kV/50 Hz transmission system using PSCAD/EMTDC. The performance of the proposed fault-location method was evaluated for using different angles of fault inception, fault impedances, sampling rates, and noise. The fault-location method proposed in this paper was verified using real-world testing, which involved taking measurements from a TW-based fault-location device.

A Novel Transmission Line Fault Location Method Based on Time Frequency Correlation

The fault location method based on the transient traveling wave has been widely used in power grid. The location accuracy and reliability of traveling wave fault location may get affected by some factors including: length error of transmission line, timing error, secondary signal cable in substation. The paper proposes a novel fault location method based on the time-frequency correlation of the fault data collected from two ends of transmission line. It takes advantage of the symmetry and similarity of reflected waves at both ends while the resonance and the reflected waves of adjacent lines are not correlated with each other. Through time-frequency correlation analysis at both ends, the influence of interference and resonance is suppressed, reliability of reflected wave identification and fault location, as well as accuracy of fault location are improved. Effectiveness of the method is verified by simulation and field data.

Research on Transmission Fault Location Based on Scanning Data

Aiming at the problem that the conventional transmission line fault location method has a delay in positioning and cannot be timely feedback, a method for fault location of transmission lines based on 3D scan data matching is proposed. 2D feature points are used to obtain three-dimensional point pairs. Structured light projectors and 3D scanning technology are applied to match image feature points and generate mapping relationships with reconstructed 3D space points. Then use point cloud computing to solve three-dimensional coordinates and use features. Click the interpolation result to complete the data matching process. The simulation experiment applies the 3D scanning data matching technology to the operation process of transmission line fault location. The experimental results show that compared with other methods, the method of this paper has the highest detection stability and the advantage of high accuracy of intelligent fault diagnosis, and can give feedback on transmission line faults in time.

Time-Domain Transmission Line Fault Location Method With Full Consideration of Distributed Parameters and Line Asymmetry

Accurate fault location reduces operating cost and outage time. This paper proposes a time-domain method to accurately locate faults in transmission lines, which only requires a very short data window (several milli-seconds) during faults. First, the voltage distribution through the line during faults is accurately obtained by solving the matrix form partial differential equations using the proposed numerical scheme. The proposed numerical scheme is mathematically validated for the transmission line fault location problem, with the optimal selection of time and distance intervals to ensure stability and minimum solution error. Afterwards, the fault location is obtained via the extremum value of the voltage distribution. The method fully considers distributed parameters as well as asymmetry of the line. Extensive numerical experiments validated that (a) the proposed numerical scheme demonstrates advantages towards other numerical schemes; (b) the proposed method presents higher fault location accuracy compared to the existing method, independent of fault types, locations and impedances; and (c) the fault location accuracy is not sensitive towards fault inception angles, loading conditions, measurement errors and parameter errors. The proposed method works with relatively low sampling rates (80 samples per cycle) and is compatible with IEC 61850 standard in present digital substations.

Precise Traveling Wave-Based Transmission Line Fault Location Method Using Single-Ended Data

In this article, an accurate single-ended traveling wave-based fault location method is proposed for transmission lines with the inputs as the first three arrival times of traveling wave wavefronts and wave velocity of the line. In the calculation process, two fault distances are obtained considering the fault in the first or second half segment of the line by using the first (incident) and second (reflected) wavefronts. The third wavefront is then used to determine the faulted half segment and thereby select the correct fault distance out of the two. The technique is economical, and it does not require communication. The proposed technique is verified on a 400 kV, 50 Hz, 150 km two-terminal line using EMTDC simulations with a realistic line model. The performance of the method is evaluated for different fault locations, fault inception angles, and fault resistances. The test results obtained by the proposed method are compared with a practically proven two-terminal communication-based method and are found to be accurate.

Study on T-Connection Transmission Line Fault Location Method Based on Transient Fault Traveling Wave Signal

Aiming at the fault location of T-type transmission lines, which are susceptible to the influence of wave speed and transmission line length, this paper proposes a method of T-type transmission line fault location based on transient fault traveling wave information. Based on the fault reflection traveling wave generated at the fault point of the transmission line when a fault occurs, this paper detects the current and voltage traveling wave of the transmission line before and after the fault occurs through a current and voltage collector, and uses the non-stationary signal analysis to obtain the fault line The initial time of the wave reflection to the transmission line port is obtained by simplifying the formula to obtain the modal maximum value of the initial time of the transient fault traveling wave. The modal maximum value of the initial reflected traveling wave time is brought into the calculation formula of the fault branch location criterion. Finally determine the fault distance. Experimental results based on PSCAD show that the method has better accuracy and efficiency than traditional fault analysis methods.

Mathematical development of the sampling frequency effects for improving the two-terminal traveling wave-based fault location

This paper presents a deep analysis of sampling frequency effects on the classical two-terminal traveling wave-based transmission line fault location method performance, demonstrating that these effects can be represented by well-defined regions (in the format of lozenges) in a time-space plane. Thereby, it is demonstrated that the classical method estimates the fault location in predefined points due to sampling frequency-associated time resolution. Furthermore, faults at the same location can be randomly estimated in different predefined locations depending on the fault inception time, resulting in location uncertainties. Nevertheless, the proposed time-space lozenges support a probabilistic analysis in order to consider the sampling frequency effects by adding a probabilistic search field component to the classical fault location formulation which indicates the region in which the fault took place with 100% of certainty regarding the sampling frequency effects. Therefore, this paper also proposes an improvement on the classical method by considering the effects of the sampling frequency. The proposed approach was evaluated by means of digital simulations and validated experimentally in laboratory by the application of faults along a 1 km long cable.

Fault Location Using Sparse Synchrophasor Measurement of Electromechanical-Wave Oscillations

This paper presents a novel system-wide fault-location method for transmission lines utilizing electromechanical-wave oscillation propagation phenomena. The method uses synchrophasor measurements during disturbances obtained from phasor measurement units sparsely located in the network. The method determines the time of arrival of electromechanical waves propagating from the fault point to sparsely located phasor mesaurement units. By taking the speed of electromechanical-wave propagation as well as topology of the network into account, the method is able to detect the faulty line. Finally, by adding fictitious buses inside the faulty line and applying a binary search method, the location of fault is accurately pinpointed. The main advantage of the proposed method is the use of a limited number of PMUs which reduces the cost of implementation. The method was developed in MATLAB and tested with the IEEE 118-test system. Test results reveal the high accuracy of the method in detecting and locating faults.

Improved Fault Location Through Analysis of System Parameters During Autoreclose Operations on Transmission Lines

This paper describes a novel single-ended impedance-based fault-location method for transmission lines, which is based upon the analysis of voltage and current during discrete system states that arise during the operation of single- and three-phase autoreclose schemes. A fault-location estimation algorithm, using the data measured during various system states and is capable of locating the fault types involving one fault resistance (i.e., single-line-to-ground fault or line-to-line fault), is developed and presented. The proposed fault-location technique is shown to have high accuracy; results are presented and compared with the well-established Takagi method and the performance of the algorithm is analyzed and discussed. The proposed technique can reduce or negate limitations associated with conventional single-ended methods and can also estimate other factors associated with the fault (e.g., fault resistance and remote source impedance). In addition, it is a potentially economic solution, since it is relatively straightforward to implement on a standard protection relay hardware platform. The proposed method is demonstrated using Electromagnetic Transients Program/Alternate Transients Program simulation models for a variety of different cases. This paper concludes with an overview of ongoing and future work that has the intention of moving the work forward toward implementation within commercially available relay hardware.

Accurate Single-Phase Fault-Location Method for Transmission Lines Based on K-Nearest Neighbor Algorithm Using One-End Voltage

In this paper, some useful features are extracted from voltage signals measured at one terminal of the transmission line, which are highly efficient for accurate fault locating. These features are the amplitude of harmonic components, which are extracted after fault inception through applying discrete Fourier transform on one cycle of three-phase voltage signals and then are normalized by a transformation. In this paper, the location of single-line-to-ground faults as the most probable type of fault in the transmission networks is considered. The SLG fault locator, which is designed based on the simple algorithm of k-nearest neighbor ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> -NN) in regression mode, estimates the location of fault related to the new input pattern based on existing available patterns. The proposed approach only needs the measured data from one terminal; hence, data communication between both ends of the line and synchronization are not required. In addition, current signals are not used; therefore, the proposed approach is immune against current-transformer saturation and its related errors. Tests conducted on an untransposed transmission line indicate that the proposed fault locator has accurate performance despite simultaneous changes in fault location, fault inception angle, fault resistance, and magnitude and direction of load current.

Transmission Line Fault Location Using Two-Terminal Data Without Time Synchronization

This letter presents a new transmission line fault location method that uses current and voltage sinusoidal phasors at both ends, without necessity of data synchronization. The main difference among the classical Johns method resides in the fact that the proposed method is based on magnitude of fault point voltage and does not demand exact phase angles of the acquired signals. Simulated and real case results are presented, showing that the proposed algorithm is robust, accurate, and provides adequate performance. Practical applications confirm that the synchronization is not really necessary, making the method faster and easier to apply than classical methods in many real situations

Fault Location on a Transmission Line Using Synchronized Voltage Measurements

Many methods for fault location using synchronized phasor measurement have been reported in literature. Most of these methods use voltage and current measurements at one or both ends of a transmission line. Accuracy of current measurement is limited by the accuracy of the current transformers (CT) used. This paper describes a fault-location method for transmission lines using only synchronized voltage measurements at both ends of the line, eliminating the inherent error due to CT. The method can be applied to transposed and untransposed lines. The method is tested using results from a steady state fault-analysis program and EMTP.