Proposed Fault Location Method Research Articles

Traveling-wave-based Fault Location using Time Delays between Modal Components in Electrical Distribution Systems

Background: The distribution feeders usually include many laterals, too many sensors need to be installed to locate the fault positions in electrical distribution systems by using the traditional double-ended traveling-wave-based fault-location methods Objective: Fault location based on the time delays between the moments of the first wavefronts of zero-mode voltages and that of aerial-mode voltages arriving at one end of the distribution feeder. Methods: Large decomposition level in wavelet transformation is adopted in this paper to obtain the zero-mode velocity. Results: Both theoretical research and simulation experiments have proved that the proposed fault location method can greatly improve the accuracy of the fault location in the electrical distribution systems without many sensors. Conclusion: The proposed fault location method can provide one feasible way to locate the faults in the electrical distribution systems.

A Novel Machine Learning-Based Approach for Fault Detection and Location in Low-Voltage DC Microgrids

DC microgrids have gained significant attention in recent years due to their potential to enhance energy efficiency, integrate renewable energy sources, and improve the resilience of power distribution systems. However, the reliable operation of DC microgrids relies on the early detection and location of faults to ensure an uninterrupted power supply. This paper aims to develop fast and reliable fault detection and location mechanisms for DC microgrids, thereby enhancing operational efficiency, minimizing environmental impact, and contributing to resource conservation and sustainability goals. The fault detection method is based on compressed sensing (CS) and Regression Tree (RT) techniques. Besides, an accurate fault location method using the feature matrix and long short-term memory (LSTM) model combination has been provided. To implement the proposed fault detection and location method, a DC microgrid equipped with photovoltaic (PV) panels, the vehicle-to-grid (V2G) charging station, and a hybrid energy storage system (ESS) are used. The simulation results represent the proposed methods’ superiority over the recent studies. The fault occurrence in the studied DC microgrid is detected in 1 ms, and the proposed fault location method locates the fault with an accuracy of more than 93%. The presented techniques enhance DC microgrid reliability while conserving renewable resources, vital to promoting a greener and more sustainable power grid.

A novel fault location method for the active distribution network based on dynamic quantum genetic algorithm

AbstractThe fault location of an active distribution network is a vital analysis to prevent major outages in the power system. Considering the influence of renewable distributed generations on fault characteristics, this paper proposes a novel location method based on a dynamic quantum genetic algorithm to solve for fault locations in active distribution networks. In the method, the fault current code is measured based on feeder terminal units. A universal switching function is presented to convert the feeder switch status into an uploaded fault current code. The fault location model is defined as an optimization problem that presents the evaluation objective function with an anti-false-positive factor. The dynamic quantum genetic algorithm is developed to locate the fault feeder according to the uploaded fault current code of the feeder terminal unit. The algorithm adopts dynamic rotating gate strategy and adaptive quantum crossover strategy to satisfy the requirements of quickness and accuracy for fault location. Moreover, the method avoids easily falling into a local optimum by integrating the discrete quantum mutation. The proposed fault location technique is tested and compared to other existing techniques on a 33-bus active distribution network. The simulation results show that the proposed fault location method can locate fault feeders accurately with fast computational times under conditions of single or multiple faults and with an information distortion of the feeder terminal unit.

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.

Design of fault location algorithm based on online distributed travelling wave for HV power cable.

To tackle the challenge of localization failure due to traveling wave dispersion during a mid-line fault in a long high-voltage cable, this study conducts an in-depth analysis of the refraction characteristics of the cumulative three-phase sheath currents at cross commutation points and direct grounding points, facilitated by detailed theoretical derivation. We introduce the novel concept of a 'first traveling wave attenuation index,' which quantifies the peak of the initial faulted traveling wave. We strategically place distributed traveling wave detection devices solely in the first direct grounding box of each cross-interconnected main section, effectively segmenting the line into five distinct zones. These zones are identified based on the unique transient polarities exhibited by the first traveling wave of fault current at each impedance mismatch point along the cable. To overcome the issue of weak traveling wave signals collected at the first end measurement point, we propose an innovative peak detection method for the first wave. This method harnesses the power of empirical wavelet transform (EWT) and multi-resolution singular value decomposition (MRSVD), providing a significant boost in ranging accuracy compared to traditional wavelet methods. Simulation results validate the efficacy of our proposed fault location method, which accurately pinpoints the fault section by contrasting the polarity of the first wave peak of the sheath current detected at each measurement point. Notably, our method ensures safety and convenience as the equipment does not require direct contact with high voltage.

A new fault location scheme based on local measurements for transmission lines connected to inverter-based resources

This paper aims to reveal conventional impedance-based fault location methods’ shortcomings in the presence of inverter-based resources (IBRs) through an analytical framework established for the analysis of the IBR sequence impedances. Thereafter, a single-ended method is put forward in order to accurately specify the fault location in the lines emanating from the IBRs. The proposed fault location formulation utilizes the negative and zero sequence currents as alternative polarizing currents, therefore it is independent of the pre-fault data, and it can be applied for all kinds of asymmetrical short circuit fault. Furthermore, the established formulation is further amended to make it applicable to long transmission lines. The suggested method also provides acceptable accuracy in various conditions, such as different fault resistances, different host grid codes, and dynamic behavior of the fault resistance. The performance of the proposed scheme is scrutinized using the PSCAD/EMTDC software with an extensive number of simulations. The obtained results reveal the effectiveness and efficacy of the proposed fault location method in the presence of IBRs.

Flexible DC distribution network fault location method based on beetle swarm optimization algorithm

To improve the fault location ability of the DC distribution network and ensure its power supply reliability, a fault location method based on the beetle swarm optimization algorithm is proposed. Firstly, the fault characteristics of the DC side after short-circuit fault are analyzed, and the mathematical model for fault location is established; then, the problem of fault location is transformed into the problem of parameter identification by discretization; finally, to verify the effectiveness of the method, a flexible DC distribution network model is built in MATLAB. The simulation results show that the proposed fault location method is accurate, not affected by the transition resistance, and has good robustness.

Converter valve-level fault location method based on the temporal differences among horizontal and longitudinal valve states

AC fault or converter fault could lead to LCC-HVDC converter protection operation, and converter protection outlet involves a random bypass pair scheme, which would expand the fault. To address this issue, a converter valve-level fault location method based on temporal differences among horizontal and longitudinal valve states is proposed. The research focuses on the inverter as the object, and analyzes the circuit state characteristics at the different fault locations within converter. In the horizontal direction of converter structure, conduction widths of AC current are constructed based on the location of commutation groups. In the converter longitudinal direction, temporal features of conduction widths are constructed based on single bridge or two bridges. Firstly, fault area is identified based on the amplitude characteristics of converter terminal currents and the abnormal characteristics of valve states. Secondly, converter internal fault is located by using the difference in the horizontal conduction width and the longitudinal temporal features between two bridges. Thirdly, the faulty phase or faulty valve is located as the valve that has the greatest virtual conduction width within the time window interval. Finally, simulations and field record data verify the validity of the proposed fault location method, and show that the proposed method has strong adaptability.

Detection of single-phase-to-ground faults in distribution networks based on Gramian Angular Field and Improved Convolutional Neural Networks

Fault detection of transmission lines is a fundamental guarantee for the stable operation of the power grid. The characteristic information is not obvious when a single-phase-to-ground fault occurs in the complex distribution network, and the existing methods are vulnerable to the problems of fault conditions and environmental noise. To address this problem, a new method of distribution network fault diagnosis is proposed based on Gramian Angular Field (GAF) and Improved Convolutional Neural Networks (ICNN) in this paper. Firstly, the time-series signals are normalized and transformed to a polar coordinate system. The encoded signals are converted into visual virtual images through the inner product calculation of GAF algorithm. Secondly, multi-scale module and attention mechanism are added to the convolutional layer of the ICNN. Among them, the multi-scale module, which enhances the local feature extraction capability for the original image, is composed of multiple convolutional channels. The purpose of attention mechanism is to help the weight distribution and depth feature filtering of ICNN, focusing on the key features between fault data. Finally, the transfer learning method is further introduced to improve the fault diagnosis model performance for different online situations. The experimental results show that the overall accuracy of the proposed fault location method is close to 99% under different topological situations. Even with the influence of ambient noise, the accuracy of GAF-ICNN still approaches 97.5%.

A Less-Invasive Method for Accurately Diagnosing Demagnetization Fault in PMSM Using Rotor Partition

This paper presents a less-invasive method for accurately diagnosing of demagnetization fault in permanent magnet synchronous motors (PMSM) using rotor partition. The rotor PMs are partitioned according to certain rules. The PMs condition of each partition is sequentially diagnosed through the signals measured by two additional toroidal yoke coils, thus the conditions of all rotor PMs are diagnosed. Firstly, the working mechanism of the search coil is analyzed, and the partitioned model of SC residual voltage is also presented. Secondly, the relationship between residual voltage signatures of SC and different demagnetization fault modes is studied by the established model. From the analysis, a demagnetization fault location method is proposed. The simulation and experiment results validate the correctness of the proposed method and indicate the proposed fault location method applies to the online diagnosis of both local and uniform demagnetization faults. In addition, the location of demagnetized PMs can be detected under any demagnetization fault condition and is not affected by other fault signals. Lastly, a comparison with existing methods based on search coil is performed and indicates the proposed method can locate faults more quickly and accurately than that of existing methods when the PM is demagnetized by 10%, and it is less invasive, especially has advantages in locating demagnetization PMs in PMSM with numerous pole-pairs. This article provides a new idea for demagnetization fault location of PMSM, as well as provides a significant reference for a motor maintenance schedule and fault-tolerant control of PMSM.

Faulted Line-Section Location in Distribution System With Inverter-Interfaced DGs Using Sparse Meters

This paper proposes a faulted line-section location method using sparse meters for the distribution networks (DNs) with high penetration of inverter interfaced distributed generations (IIDGs). By modeling the IIDGs as equivalent impedances instead of current sources, the fault component model of the DN with IIDGs can be transferred from a multi-current feeding system towards the sole-current feeding system. On this basis, the Bayesian Compressed Sensing (BCS) algorithm is applied to achieve the sparse solution of the fault current to indicate the faulted line-section. Moreover, to reduce the required meters for monitoring the IIDGs, a node partition scheme is designed based on the analysis of IIDG with different control strategies. The proposed fault location method requires only 15 meters for an IEEE 69-node distribution network with 20 IIDGs. Simulation results show that the location success rate is beyond 95% for various fault scenarios which is a 55% improvement over the existing BCS-based method.

A novel fault location method for hybrid lines based on traveling wave

In this paper, a novel fault traveling wave-based location method for hybrid lines is proposed. According to the refraction characteristics of fault traveling wave (TW) at junction nodes, the node ratio coefficient value Q is defined based on the amplitude of traveling wave. Then, by comparing the Q values of junction nodes and fault points, a fault section identification principle is proposed to determine the fault line section for hybrid lines. After identification of fault line section, a double-ended fault location method is revised via adding the location compensation factors to mitigate the effect of traveling wave velocity changes on fault location for multi-section hybrid lines. Additionally, considering the detection problems of arrival time for TW signals, the extreme-point symmetric mode decomposition (ESMD) method and Teager energy operator (TEO) are proposed. The ESMD method is applied to decompose the sampled fault traveling wave signals into several intrinsic modes to filter out the fundamental frequency and low frequency signals. The TEO is employed to track the characteristics of TW signals. Effectiveness of the proposed method is validated in PSCAD. Results show that the ESMD-TEO can detect TW signals effectively, and the proposed fault location method can determine the fault line section and locate fault positions correctly.

Fault location for overhead and cable hybrid transmission lines based on the difference quantities of forward propagating waves and backward propagating waves in HVDC systems

This paper proposes a novel method to locate faults for overhead and cable hybrid transmission lines. Using the difference quantity of the forward propagating wave and the difference quantity of the backward propagating wave of DC currents at both ends of the line, the fault segment decision function is defined, and based on the different values of the decision function when a fault occurs in different segments, the fault segment is determined. The two equations for the relationship between the fault distance and the difference quantities of the forward current propagating wave and the backward current propagating wave are listed, respectively. Based on the fact that the fault currents in the two equations are equal at the fault point, the intra-segment fault location equation is established, and using the particle swarm optimization algorithm, the nonlinear location equation is solved. This paper also studies the matching pursuit algorithm to adaptively extract the DC component in the fault transient stage. An HVDC system simulation model with an overhead and cable hybrid transmission line is built on the PSCAD/EMTDC platform, and the simulation results show that the proposed fault location method is effective.

Fault location method of IGBT short-circuit for a grid-tied Neutral-Point-Clamped inverter system

For the Neutral-Point-Clamped (NPC) three-level grid-tied inverter, when IGBT short-circuit happens, the hardware protection would be triggered immediately to block all drive signals. After the system shuts down the fault location cannot be learned. This paper proposes a short-circuit fault location method for the internal switches of the NPC topology, based on the current loop analysis after system shuts down. The proposed method does not need to add additional sensors, only by means of the existing monitoring data can be completed fast diagnosis. The experimental results verify the feasibility and effectiveness of the proposed fault location method.

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.

Fault source location of wind turbine based on heterogeneous nodes complex network

Previous studies regarding wind turbine health management based on wind turbine supervisory control and data acquisition (SCADA) signals focused on detecting incipient failure. In this case, most current SCADA alarm systems adopt a single or multi-signal threshold trigger alarm. When a wind turbine is operating in a large wind farm, it is catastrophic for maintenance personnel lied in the reason that the current SCADA system may trigger many alarms in the short term. Therefore, the fault source must be identified and the candidate fault sources sorted. This study aims to obtain the fault location of wind turbines based on a complex network, which does not require a large number of historical monitoring signals. A directed graph of the wind turbine and fault location theoretical framework is established; an improvement is achieved based on the heterogeneity of nodes abstracted by components of a wind turbine and variables of SCADA. The proposed fault location method based on heterogeneous nodes complex networks (HNCN) is improved based on degree-based mean-field theory and is verified by spreading simulated data and four SCADA alarm cases at a wind farm located in Liaoning, China.

Transient and steady-state faults location in intelligent distribution networks compensated with D-STATCOM using time-domain equations and distributed line model

Intelligent electric distribution networks compensated with D-STATCOM are active networks in which data of terminals is important for better distribution of energy. Similar to all electricity network devices, energy distribution lines in such networks are also subject to transient and steady-state AC faults, e.g., short circuit. Sections of the network in which the fault occurs are separated by relays. In such a condition, fault location and restoring the normal status of the network are important. Fault location in these networks is performed based on synchronous data of two terminals because data of all buses are transmitted to the main bus In this paper, a time-domain equation method (TDEM) is proposed for locating faults on smart distribution grid (SDG) using distributed line model based on time-domain equations. The proposed method locates the point of transient and steady-state fault in SDG considering DGs and compensators. In this paper, the D-STATCOM and wind power plant are considered in SDG. The suggested method does not need the D-STATCOM and DGs model for applying the algorithm. It only uses data of less than half of the cycle for executing the algorithm. The numerical simulation confirms that the proposed fault location method is accurate and it provides a reliable solution for automatic fault location problem in distribution networks.

Research on Fault Location in Distribution Network Based on Fast Fault Transfer Arc Extinguishing Device

In the distribution network equipped with fast fault transfer arc extinguishing device, after a single-phase grounding fault occurs, the fault phase bus is quickly grounded to realize arc extinguishing. At the same time, the traveling wave signal generated during the grounding process of the fault phase bus can realize fault location. The traveling wave signal is subjected to phase-mode transformation, and the time difference of the zero-mode component mutation detected twice at the exit of the fault line is to be recorded. This time difference is the time which it takes for the zero-mode component to go to and fro once between the bus and the fault point. And then the fault distance can be calculated based on it. The integration of arc extinguishing and fault location is realized. The AT P simulation software is used to realize the fault simulation of distribution network. And the accuracy and feasibility of the proposed fault location method are verified.

Novel Faulted Section Location Method for Distribution Network Based on Status Information of Fault Indicating Equipment

This paper proposes a novel faulted section location method for power distribution networks based on the status information collected by fault-indicating equipments. It has an advantage that it does not need to analyze and calculate any electrical parameters, and it is not affected by fault types and system parameters, so this method can be easily applied to power distribution networks. Firstly, a novel method for automatically constructing a line list is proposed in this paper—it can represent the topology structure of the power distribution line and the status information of fault-indicating equipment. Based on the line list, a topology search algorithm is proposed in the method to locate the faulted section. Considering that information loss will cause errors in the line list, an information loss detection algorithm is proposed to detect and correct the wrong status of fault-indicating equipments. Then, different fault conditions such as single fault, multiple faults, distributed generations in system and information loss condition are tested in power distribution networks with different topologies, and the simulation results indicate that the proposed method can deal with each case well. Moreover, the proposed fault location method has an advantage that the running time does not necessarily increase when the node scale is expanded.

Improving the wide-area PMU-based fault location method using ordinary least squares estimation

This paper presents an approach which allows system-wide fault location using only a sparse set of synchronized phasor measurements. The proposed algorithm combines post-fault voltage prediction and sparse estimation. The resulting method enables practical application of the sparse estimation formulation by using Prony analysis to predict post-fault steady-state voltages at those buses equipped with phasor measurement units. The prediction requires only a short transient recording which is typically available before the actuation of protective relays. Following the prediction step, the least angle regression based sparse estimation algorithm is employed to identify the fault location. However, for particular conditions usually associated with small fault currents, the sparse estimation algorithm may not be able to correctly identify the fault location. To mitigate this problem, ordinary least squares is used to increase the robustness of the proposed method. A 3-Phase model of the IEEE 118 bus system is developed on the alternative transients program to simulate realistic fault transients and test the performance and accuracy of the proposed fault location method.