Proposed Fault Location Scheme Research Articles

A fault location scheme based on composite traveling wave with transients in adjacent fault-free lines

As the speedy expansion of power gird, the traveling wave fault locator in substation may not always connect to newly added transmission lines in time, which reduces the effectiveness of fault locator. In this paper, an adjacent fault-free line based fault location scheme for newly additional line is proposed. Since the traveling wave from adjacent fault-free line results in severe difficulty for identification of traveling waves from faulty line, the time–frequency matrix is performed to screen traveling waves. Firstly, in order to remove the influence of waves from remote terminals of adjacent fault-free line, the current refraction coefficient is theoretically analyzed. Due to the negative refraction coefficient, traveling waves from remote terminals of adjacent fault-free line can be reduced by the proposed composite traveling wave. Secondly, the time–frequency matrices of composite traveling wave and original traveling wave is obtained by S-transform. Then, these matrices are applied to form ratio matrix which thoroughly eliminated waves from remote terminals of fault-free lines. Moreover, the robustness of the proposed fault location scheme is thoroughly validated by the simulation of PSCAD/EMTDC. Finally, the proposed fault location method has the great accuracy in simulation tests and field data test.

A new fault location scheme for parallel transmission lines using one-terminal data

This paper proposes a fault location (FL) scheme for a two-terminal double-circuit transmission line using one-terminal current and voltage measurements. As the proposed scheme is formulated in the phase-coordinates, the parallel transmission lines are not required to be decoupled, and the proposed scheme can be applied for transposed or untransposed lines. In addition, the proposed scheme takes into account the line asymmetry and the potential couplings between the phases of the same circuit or different circuits. The derived FL equation is based on two concepts. The first concept is that the fault impedance is mainly resistive component. The second one is that the voltages of the similar phases in both circuits at each line terminal are equal to each other. Further, a new fault classification method is introduced to recognize the faulted phases, which are initially required to apply the proposed FL scheme. Moreover, the IEEE 39-bus system is deployed as a test case, and it is simulated on PSCAD/EMTDC software. The frequency-dependent phase model is used to emulate the parallel transmission lines. All fault types, including the cross-circuit faults, are tested considering different fault resistances and locations. In addition, the effect of the measurement errors on the fault location accuracy is investigated.

Fault location measurement of sensor nodes based on fuzzy control algorithm

The sensor nodes are devices with extra capabilities of sensing, communicating and processing of the recorded data. The sensor-based wireless and IoT-enabled networks can contribute a precarious part of army command, defense control, defense communications, computerized based intelligence and surveillance, and above all the targeting systems. Examples of defense applications include monitoring of own army forces and enemy forces; monitoring of ammunition, monitoring of equipment, targeting at certain regions; and nuclear as well as biotechnology-based attack detection. With the advent of AI and latest technologies, a technical paradigm shift can be seen in monitoring the faults in sensor nodes that are capable to collect the data and entire decisions are inferred on the basis of this data. By deploying sensors in critical areas, all the movements can be followed in detail. Hence, instant fault location measurement of sensor nodes with the least complex approaches is the need of the hour. Therefore, a novel soft computing-based approach is proposed in this paper for measuring the fault in locations of sensor-based networks using fuzzy logic and neural networks with high accuracy. The proposed technique allows lower consumption of energy while locating the faults. The results demonstrate the superior performance of the proposed fault location scheme with respect to the network node loss, measurement error, and measurement time taken for detecting faults in locations of sensor nodes. The proposed fuzzy and neural network-based method outperforms the existing benchmarked techniques considered for comparative study.

Optimized ensemble of regression tree-based location of evolving faults in dual-circuit line

In a dual-circuit transmission line, the location of evolving faults (EVFs) is more tiresome due to its multifaceted nature. In this paper, a novel data-mining-based scheme is proposed for location of EVFs by using an ensemble of regression trees, that is, bagged regression trees and boosted regression trees. This ensemble of regression tree modules is trained with optimized hyperparameters such as minimum leaf size, leaning cycles, and learning rate by using Bayesian optimization. A practical power transmission network of Chhattisgarh state is modeled/simulated in MATLAB software to employ the proposed fault location scheme. Exclusive datasets are provided by performing extensive simulation studies at a wide range of fault scenarios, thereby applying discrete wavelet transform as an explanatory signal processing technique. Further performance assessment is carried out by comparing different error metrics such as mean absolute error, mean absolute relative error, mean square error, and root mean square error. The simulation results confirm the applicability of the proposed scheme for fault location estimation, and it makes a research insight while designing relaying schemes to practical power transmission networks.

Fault Location Scheme for Cross-Country Faults in Dual-Circuit Line Using Optimized Regression Tree

In the double-circuit transmission line (DCTL), location of cross-country faults (CCFs) is more wearisome due to its intricate nature. The CCFs can occur at miscellaneous locations on dissimilar phases at the same fault inception time. Furthermore, the CCFs encompasses different fault locations which can mislead the line patrolling team and not only takes long hours to attend the fault location. Therefore, this may also cause electrical stress on the various power system components owing to tripping of circuit breaker repeatedly because of inappropriate fault clearance. In this context, an ensemble of regression tree (ERT) model-based fault location scheme is proposed using different regression trees such as Bagged Regression Trees (BGRT) and Boosted Regression Trees (BSRT). These regression tree modules have been trained with optimized hyper-parameters such as minimum leaf size, leaning cycles, and learning rate by using Bayesian optimization. A 400 kV, 50 Hz Chhattisgarh state power system (CSPS) network has been designed and simulated in MATLAB/Simulink to implement the proposed fault location scheme. Exclusive datasets have been designed at atypical fault scenarios thereby applying an exploratory signal processing technique such as Discrete Wavelet Transform (DWT). Additionally, the performance assessment has been done by comparing different error metrics. The simulation results reveal the applicability of the proposed ensemble regression tree (ERT) model for location of CCFs and it gives a research insight to adapt the same in the real power system network.

Asynchronous Fault Location Scheme Based on Voltage Distribution for Three-Terminal Transmission Lines

The synchronization of the voltage and current from different terminals is generally unachievable in the power grids at mountainous area, which leads to the fault location method with synchronized data to be impossibly utilized. This paper proposes a voltage distribution based fault location scheme with asynchronous data for three-terminal transmission lines. At first, the faulty section is identified by the voltage computed from each terminal due to the boundaries formed by fault point and tee-point. Since the fault current is stable after the transients decay, the asynchronous calculated voltage and current from the terminals without faults can be synchronized by their angle differences to form the voltage and current at faulty section near the tee-point. Then, the voltage distribution of the faulty section can be obtained from the tee-point and the terminal to find the intersection point of them. In order to fully utilize the fault characteristics in the voltage and current, the earth mode and the minimum of the voltage distribution are applied to optimize the fault location results for grounding faults and multi-phase faults, respectively. Moreover, the robustness of the proposed fault location scheme is thoroughly validated by the simulation of PSCAD/EMTDC. At last, a set of the field data acquired by wave recorders is applied to test the feasibility of the proposed approach.

Localized Protection of Radial DC Microgrids With High Penetration of Constant Power Loads

This article proposes a localized protection scheme for dc microgrids with radial configuration under the impact of constant power loads (CPLs) to determine the location of faults accurately. The proposed fault location scheme is primarily designed for fault location of CPLs in dc microgrids. First, a local protection relay for CPL is designed based on the transient behavior of the current and voltage in the main distribution line. Then, the estimation of the fault resistance is formulated based on the power sharing in the system to improve the accuracy of the protection system. To realize a robust protection scheme considering the variation of fault resistance, a fault resistance estimation procedure is employed to design a system that locates both low- and high-impedance faults. Finally, the effectiveness of the proposed strategy is evaluated based on offline digital time-domain simulations in Digsilent PowerFactory software environment and experimentally verified by implementing on a laboratory scale hardware setup. The obtained simulation and experimental test results, and comparison with other methods prove that the proposed scheme is immune against these disturbances and can efficiently and reliably estimate the location and resistance of faults with high accuracy and acceptable error margin.

Fault location in multilateral distribution network with electric vehicle charging load

AbstractIn a multilateral distribution network, faults at different locations can generate the same voltage and current at the substation; hence, the calculated fault location can correspond to several places in the network. To avoid this major problem, a two‐terminal travelling wave‐based fault location method is presented in this article, which at first identifies the faulted lateral in the distribution network and then estimates the exact fault location. The proposed fault location scheme uses wavelet energy entropy of the recorded three‐phase current signals and the magnitude of ground mode component wavelet modulus maxima (WMM) for fault detection and fault type identification in the network. After that, the faulted lateral identification followed by the exact fault location is performed using the aerial mode component WMM of the fault‐generated current transients. Since the integration of electric vehicle (EV) charging load is increasing day by day to the distribution network, the performance of the proposed algorithm is tested with EV charging load along with distributed generation integrated into the distribution network. Modeling and simulation of the distribution network and EV load are performed in MATLAB/SIMULINK. The simulation results show that the proposed method can accurately locate fault under different operating conditions.

Asynchronous fault location scheme for half‐wavelength transmission lines based on propagation characteristics of voltage travelling waves

Due to prominent attenuation of travelling waves, double-end fault location method produces considerable errors when applied to ultra-high voltage AC half-wavelength transmission (UAHT) lines. In order to address this problem, this study presents a novel fault location scheme based on the attenuation, refraction and reflection principles of aerial-mode voltage travelling waves (AVTWs). In the scheme, the faulted section of an UAHT line is first determined according to the accumulated amplitude ratio of the pre-determined frequency components of AVTWs asynchronously sampled at both terminals of the line. Then, the Teager energy of the first two wavefronts of the AVTW - measured at the terminal in the faulted section - is used to define two factors for selecting the appropriate accurate fault location method. Finally, the single-end travelling wave method is adopted for locating the faults near the line terminal. The presented double-end method utilises the amplitude ratio of AVTWs to locate the faults far from the line terminal. A 1000 kV UAHT line model is considered with various fault conditions in PSCAD/EMTDC simulations. The simulation results and analysis demonstrate that the proposed fault location scheme is accurate and immune to fault distances, fault types, fault impedances and fault inception angles.

A novel single-phase-to-earth fault location method for distribution network based on zero-sequence components distribution characteristics

Based on distribution characteristics of the zero-sequence voltages and currents of the distributed lines, this paper proposes a novel single-phase-to-earth fault (SPTEF) location scheme for distribution network. Firstly, the distributed parameter model of distribution feeder lines is appropriately simplified according to Taylor series expansion of the hyperbolic functions in the model. The fault factor is constructed to select the faulted feeder. Then, the distribution features of the zero-sequence voltage (ZV) along the feeder line are analyzed. In each section of the faulted feeder, golden section search algorithm is adopted to distinguish the faulted section. Finally, based on the concept of maximum fault current, accurate fault location is realized by genetic algorithm (GA). A radial distribution network model containing different types of distribution lines is established in PSCAD/EMTDC. The calculation results of MATLAB prove the validity, reliability and accuracy of the proposed fault location scheme.

Fault Location in Ungrounded Photovoltaic System Using Wavelets and ANN

Identifying ground faults is a significant problem in ungrounded photovoltaic (PV) systems because such earth faults do not provide sufficient fault currents for their detection and location during system operation. If such ground faults are not cleared quickly, a subsequent ground fault on the healthy phase will create a complete short circuit in the system. This paper proposes a novel fault-location scheme in which high frequency noise patterns are used to identify the fault location. The high-frequency noise is generated due to the switching transients of converters combined with the parasitic capacitance of PV panels and cables. Discrete wavelet transform is used for the decomposition of the monitored signal (midpoint voltage of the converters) and features are extracted. Norm values of the measured waveform at different frequency bands give unique features at different fault locations and are used as the feature vectors for pattern recognition. Then, a three-layer feedforward artificial neural networks classifier, which can automatically classify the fault locations according to the extracted features, is investigated. The proposed fault-location scheme has been primarily developed for fault location in the PV farm (PV panels and dc cables). The method is tested for ground faults as well as line–line faults. These faults are simulated with a real-time digital simulator and the data are then analyzed with wavelets. Finally, the effectiveness of the designed fault locator is tested with varying system parameters. The results demonstrate that the proposed approach has accurate and robust performance even with noisy measurements and changes in operating conditions.

A Traveling-Wave-Based Fault Location Scheme for MMC-Based Multi-Terminal DC Grids

This paper presents a novel fault location scheme of DC line in modular multilevel converter (MMC)-based multi-terminal DC (MTDC) grids. Considering the low-inertia characteristics and the meshed topology, the scheme, based on traveling-wave principle, is divided into three steps, namely, faulty pole identification, faulty segment determination and fault-distance calculation. With accurate amplitude, polarities and arrival times of the first arrival current traveling waves (FACTWs) collected from time-synchronized measurements taken just at the converter stations, the proposed scheme can correctly determine the faulty pole, the faulty segment and the precise fault location. The continuous wavelet transform (CWT) is deployed to extract the required features of the input signals at the DC lines. Since the scheme merely needs the features of FACTWs, the practical difficulties of detecting subsequent traveling waves are avoided. A four-terminal MMC-based high voltage direct current (HVDC) grid was built in PSCAD/EMTDC software to evaluate the performance of the fault-location scheme. Simulation results for different cases demonstrate that the proposed fault-location scheme has high accuracy, good adaptability and reliability. Furthermore, the algorithm can be used for a MMC-MTDC grid with any number of meshes.

Advanced fault location in MTDC networks utilising optically-multiplexed current measurements and machine learning approach

This paper presents a method for accurate fault localisation of DC-side faults in Voltage Source Converter (VSC) based Multi-Terminal Direct Current (MTDC) networks utilising optically-multiplexed DC current measurements sampled at 5 kHz, off-line continuous wavelet transform and machine learning approach. The technical feasibility of optically-based DC current measurements is evaluated through laboratory experiments using commercially available equipment. Simulation-based analysis through Matlab/Simulink® has been adopted to test the proposed fault location algorithm under different fault types and locations along a DC grid. Results revealed that the proposed fault location scheme can accurately calculate the location of a fault and successfully identify its type. The scheme has been also found to be effective for highly resistive fault with resistances of up to 500Ω. Further sensitivity analysis revealed that the proposed scheme is relatively robust to additive noise and synchronisation errors.

Novel Fault Location in MTDC Grids With Non-Homogeneous Transmission Lines Utilizing Distributed Current Sensing Technology

This paper presents a new method for locating faults in multi-terminal direct current (MTDC) networks incorporating hybrid transmission media, including segments of underground cables and overhead lines. The proposed traveling wave type method uses continuous wavelet transform applied to a series of line current measurements obtained from a network of distributed optical sensors. The technical feasibility of optically-based dc current measurement is evaluated through laboratory experiments using Fiber–Bragg Grating sensors and other commercially available equipment. Simulation-based analysis has been used to assess the proposed technique under a variety of fault types and locations within an MTDC network. The proposed fault location scheme has been found to successfully identify the faulted segment of the transmission media as well as accurately estimating the fault position within the faulted segment. Systematic evaluation of the method is presented considering a wide range of fault resistances, mother wavelets, scaling factors, and noisy inputs. Additionally, the principle of the proposed fault location scheme has been practically validated by applying a series of laboratory test sets.

Fault Location Using Local Mean Decomposition on Traveling Waves with Three Current Measurements in an Overhead Conductor

A fault-location scheme based on local mean decomposition on traveling waves with three current measurements in an overhead conductor is presented herein. In the fault-location scheme, local mean decomposition is used to detect the arrival time of the initial traveling wave at each measurement. To obtain more accurate wave velocity, a third Rogowski coil current transformer is used to measure the fault current in the midway of a transmission line besides a couple of measurements used by the two-ended traveling-wave method at both its ends. The faulted line section can be identified by comparing the phase angles of the measured current data at its two ends; wave velocity can then be calculated by the ratio of the length of the non-faulted line section to the time that the fault wave travels through this line section. The proposed scheme can reduce the errors of previous methods on wave velocity determination. After wave velocity is determined, the fault distance can be calculated according to the two-ended traveling-wave method. The proposed fault-location scheme is tested by many simulations, and the results demonstrate it has higher accuracy than those using wavelet transform and Hilbert–Huang transform.

Traveling-Wave-Based Line Fault Location in Star-Connected Multiterminal HVDC Systems

This paper presents a novel algorithm to determine the location of dc line faults in an HVDC system with multiple terminals connected to a common point, using only the measurements taken at the converter stations. The algorithm relies on the traveling-wave principle, and requires the fault-generated surge arrival times at the converter terminals. With accurate surge arrival times obtained from time-synchronized measurements, the proposed algorithm can accurately predict the faulty segment as well as the exact fault location. Continuous wavelet transform coefficients of the input signal are used to determine the precise time of arrival of traveling waves at the dc line terminals. Performance of the proposed fault-location scheme is analyzed through detailed simulations carried out using the electromagnetic transient simulation software PSCAD. The algorithm does not use reflected waves for its calculations and therefore it is more robust compared to fault location algorithms previously proposed for teed transmission lines. Furthermore, the algorithm can be generalized to handle any number of line segments connected to the star point.

Identification of Fault Location in Distribution Networks Using Multi Class Support Vector Machines

Abstract This paper presents a multi-class support vector machine (SVMs) approach for locating and diagnosing faults in electric power distribution feeders. Different from the traditional Fault Section Estimation methods, the proposed approach uses measurements available at the substation and remote terminal units (RTUs). To show the effectiveness of the proposed methodology, a practical 52 nodes, 3 feeder distribution systems (DS) with loads is considered. Practical situations in distribution systems, such as protective devices (circuit breakers/isolators) placed at different locations and all types of faults with a wide range of varying source short circuit (SSC) levels and fault impedances are considered for studies. The proposed fault location scheme is capable of accurately identify the fault type, location of faulted feeder section and the fault impedance. The results demonstrate the feasibility of applying the proposed method in practical distribution automation (DA) system for fault diagnosis.

Location of DC Line Faults in Conventional HVDC Systems With Segments of Cables and Overhead Lines Using Terminal Measurements

This paper presents a novel algorithm to determine the location of dc line faults in an HVDC system with a mixed transmission media consisting of overhead lines and cables, using only the measurements taken at the rectifier and inverter ends of the composite transmission line. The algorithm relies on the traveling-wave principle, and requires the fault-generated surge arrival times at two ends of the dc line as inputs. With accurate surge arrival times obtained from time-synchronized measurements, the proposed algorithm can accurately predict the faulty segment as well as the exact fault location. Continuous wavelet transform coefficients of the input signal are used to determine the precise time of arrival of traveling waves at the dc line terminals. Two possible input signals-the dc voltage measured at the converter terminal and the current through the surge capacitors connected at the dc line end-are examined and both signals are found to be equally effective for detecting the traveling-wave arrival times. Performance of the proposed fault-location scheme is analyzed through detailed simulations carried out using the electromagnetic transient simulation software PSCAD. The impact of measurement noise on the fault-location accuracy is also studied in this paper.

Algorithm for Detecting, Indentifying, Locating and Experience to Develop the Automate Faults Location in Radial Distribution System

This paper presents the design of an algorithm to detect, identify, and locate faults in radial distribution feeders of Provincial Electricity Authority (PEA). The algorithm consists of three major steps. First, the adaptive algorithm is applied to track/estimate the system electrical parameter, i.e. current phasor, voltage phasor, and impedance. Next process, the impedance rule base is used to detect and identify the type of fault. Finally, the current compensation technique and a geographic information system (GIS) are applied to evaluate a possible fault location. The paper also shows the results from field tests of the automate fault location and illustrates the effectiveness of the proposed fault location scheme.

Traveling-Wave-Based Fault-Location Scheme for Multiend-Aged Underground Cable System

This paper presents a novel wavelet-based fault-location scheme for aged cable systems when synchronized digital fault recorded data are available at the two terminals of each cable. The proposed scheme estimates the fault location in multiend-aged cable systems using the theory of wavelet singularity detection as a powerful signal processing tool. The arrival of the first and second voltage traveling waves at both ends of the power cables can be identified reliably. The developed wavelet processing scheme is applied on the modal coordinates instead of the phase coordinates. The proposed scheme has the ability to eliminate the impact of the change in the propagation velocity of the traveling waves on the fault-location calculations. This will help solve the problem of cable changing parameters, especially the change of the relative permittivity of the cable with age. The method is valid even with faults that are very close to busbars. Characteristics of the proposed fault-location scheme are analyzed by extensive simulation studies using Alternative Transients Program/Electromagnetic Transients Program. The results indicate an accepted degree of accuracy for the suggested fault locator