Real Fault Section Estimation in Electrical Distribution Networks Based on the Fault Frequency Component Analysis

The research on fast and accurate fault location technology in distribution networks is of great significance. Currently, many methods for fault location in distribution networks have been proposed, but most theories are difficult to solve the problem of fault location in multi branch distribution networks. Therefore, this paper analyzed the characteristics of traveling wave transmission and proposed a discrimination algorithm that uses the polarity of traveling waves to determine the source of fault traveling waves; Then, using the idea of first locating the fault section and then locating the fault point, a multi branch distribution network traveling wave fault location algorithm is proposed based on the configuration of micro PMU (Phasor Measurement Units) devices in the distribution network by combining the two end method and single end method of traveling wave distance measurement. A multi branch distribution network simulation model based on IEEE14 node standard topology was built using MATLAB/Simulink software, the experimental results also showed the effectiveness and the efficiency of the proposed algorithm.

A new method of fault location of distribution network based on the tree structure diagram and improved Dempster-Shafer Theory of evidence is proposed to solve the problem of misjudgment caused by abnormal fault information in distribution network. Firstly, this paper presents a new search method based on tree structure diagram. Through the tree structure diagram, we can ensure the initial positioning result respectively based on three different alarm information. The three alarm information include fault indicator information, distribution transformer information and trouble calls. And then, through using the improved Dempster-Shafer Theory of evidence, we can integrate the initial positioning results to get the final positioning result. Finally, a concrete example is given to demonstrate the effectiveness and feasibility of this method, which indicates that the method can solve the problem when misinformation or information happens. The outstanding advantage of this method is that the multi-source information is used to locate the fault, and the misjudgment due to the abnormality of the single source information can be avoided.

The structure complexity and the extended geographical area are among the factors that create challenges in accurate fault location and detection in distribution networks. The single‐phase to ground (SPG) faults are considered as most frequent reasons for distribution network interruption, which can threaten the network's reliability. Signal processing methods are usually used as common approaches to distinguish and locate faults in distribution networks. This paper proposes a novel scenario to select optimal wavelet packet transform (WPT) coefficients for SPG fault location and a method based on superimposed voltage energy to distinguish the faulty phase according to these coefficients. Furthermore, employing the energies of the superimposed voltages helps to minimize the effects of high resistance faults (HRFs) and load encroachment on the efficiency of the faulty phase detection part. Comparing the obtained results with other scenarios demonstrates the considerable efficiency of the proposed scenario. Finally, with the help of general regression neural networks (GRNN) as machine‐learning tools, a new algorithm is derived for detecting and locating the SPG fault and capacitor bank switching overvoltage (COV). Simulation results are implemented on the IEEE 34‐bus standard distribution network, demonstrating the efficiency and superiority of the suggested method.

When the distribution network fails, the operation and maintenance personnel need to quickly determine the fault location and minimize the scope of the inspection line so that the fault repair personnel can accurately reach the vicinity of the fault point to carry out work. Whether the fault location method is advanced and reliable directly affects the power failure time of the power supply user, and further affects the social, economic, and life aspects. Therefore, the fault location of the distribution network needs to satisfy both reliability and accuracy. It is the basis and premise for troubleshooting, isolating and restoring the power supply. The automation level of China’s distribution network is relatively backward, and the reliability of power supply equipment is relatively low, making it difficult to find fault points. If we find out the intelligent algorithms that can meet the requirements of rapid positioning, accuracy and fault tolerance through theoretical research, we can Improve the fault location efficiency very well.

This paper proposes a fault location estimation method for distribution networks considering errors from measurement devices. The method determines the fault location based on the voltage sag and current magnitudes. The fault location is based on faulted section and fault distance measured from one end of the bus. Faulted section is determines by matching the measured voltage and current with a pre-developed data. For multiple faulted sections, ranking analysis is employed to rank the most likely faulted section. Fault distance is calculated from one end of the identified faulted section. By determining the faulted sections, a fault in homogenous and non-homogenous networks can be located. The method has been tested using an actual Malaysian 11 kV distribution network. Different values of measurement errors have been applied, which includes positive and negative values. The test results showed the effectiveness of the method under various uncertainty of error from measurement devices. The proposed method can serve as an alternative technique for estimating fault location in distribution networks.

The low-voltage distribution networks have some structural features, such as short supply line, more lines branch and influence of transition resistance of the short-circuit current. These characteristics seriously affect the development of fault location technology. The paper, based on the basis of the structural features about the low-voltage distribution networks, create the distribution networks of description matrix by knowledge of mathematical topology and use the distribution network fault location algorithm based on web-based structure matrix. By the algorithm, the area of fault judgment and the actual distribution network fault location are fully consistent. The new theory provides a new way of thinking for fault location in low-voltage distribution networks.

Although single phase to ground fault location in non-solid grounded networks has been studied for many years and a lot of research has been done, yet adequate solution for direct fault location of radial distribution network hasn't been made, especially for the distribution network with the neutral point grounded via arc suppression coil. Involvement of the arc suppression coil may decrease short-circuit current, but the difficulty of finding fault location is increased. The key problem of non-solid single-phase to ground fault location is to solve the fault location of distribution network with the neutral point grounding via arc suppression coil. This paper will analyse line capacitive current distribution of isolated neutral point and neutral point grounded via arc suppression coil and propose the concept of per-unit zero sequence current method. Equipartition principle of zero sequence current is utilized to locate fault section of the distribution system. Simulation tests to verify the effectiveness of this method have been made as well.

Fault location techniques play an essential role in system recovery and repair. Therefore, numerous methods have been presented for fault location in power transmission and distribution networks. The contribution of this paper is to extend the state-of-art impedance-based fault location methods to support four-wire power distribution. To make this possible an algorithm is developed. The method is obtained using the principles of circuit theory and overcomes the challenges which prevent the use of most fault location methods for distribution networks in practice. This paper presents the detailed equations which are used in the algorithm and how they are obtained. The satisfactory performance of the algorithm is confirmed with numerical examples using MATLAB software.

The use of modern methods for determining the fault location (FL) on overhead power lines (OHРLs), which have high accuracy and high speed, allows you to quickly find and repair damage. Various physical principles and algorithms for calculating the distance to the site of damage are used in FL OHРLs devices from different manufacturers. Some of algorithms for FL on OHРLs use the emergency mode parameters (EMP), other algorithms use measurement results based on wave methods. Many random factors that determine the magnitude of the error in calculating the distance to the FL affect the operation of FL devices by EMP. Methods based on deterministic procedures used in well-known FL devices for OHРLs do not take into account the influence of random factors, which significantly increases the time to search for the fault. The authors have developed a new method of FL on OHРLs using multi-hypothesis sequential analysis and the Armitage algorithm. The task of recognizing a faulted section of an OHРL is formulated as a statistical problem. To do this, the inspection area of the OHРL is divided into many sections, followed by the implementation of the procedure for FL. The developed method makes it possible to adapt the distortions of currents and voltages on the emergency mode oscillograms to the conditions for estimating their parameters. The results of the calculations proved that the implementation of the developed method has practically no effect on the speed of the FL algorithm for the OHРL by EMP. This ensures the uniqueness of determining the faulted section of the OHРL under the influence of random factors, which leads to a significant reduction in the inspection area of the OHРL. The application of the developed method in FL devices for OHРLs will ensure the required reliability of power supply to consumers and reduce losses from power outages by minimizing the time to search for a fault.

Based on the traveling wave fault location principle, the traveling wave fault location method of Teed circuit is studied, and the idea of comprehensively using the three-terminal measurement data of Teed-circuit for fault location is proposed, and a new criterion for fault branch identification and a new method for fault location are proposed accordingly. The branch identification criterion considers the influence of the actual fault location error factors on the branch misjudgment to ensure the validity of the branch identification; and the proposed fault location method makes full use of the three-terminal measurement data of Teed-circuit. Meanwhile, the influence caused by the uncertainty of wave velocity on the fault location result is eliminated in the fault location expression, and the fault location error caused by the line sags is eliminated to a certain extent. The ATP/EMTP simulation results show that the method proposed in this paper can accurately identify fault branches and locate fault points on Teed-circuit.

Fault location in distribution networks is a critical task for ensuring reliable power delivery and minimizing downtime. This paper proposes a fault location method for distribution networks based on Support Vector Machine (SVM) algorithms. The method utilizes voltage and current measurements from various network nodes to identify fault characteristics. A set of key features, including voltage sag, current surge, and their time-domain characteristics, are extracted from the data. The SVM classifier is trained on these features to differentiate between fault and normal conditions and accurately locate the fault. Experimental results using simulated data demonstrate that the proposed method significantly improves fault detection accuracy and reduces the fault location time compared to traditional techniques. The effectiveness of this method is further validated under different fault scenarios and network configurations, showing its robustness and potential for practical deployment in real-world distribution networks.

This article presents a novel fault-location method for unbalanced distribution networks in the presence of distributed generations. By utilizing the linear least square method, the candidate faulty lines are selected, and the injected fault currents are derived from the sparse voltage phasor measurements. According to the obtainability of the fault currents, two types of approaches are adopted for estimating the per-unit fault location. By taking advantage of the precise fault-location scheme, the actual faulted line and the accurate fault location are identified. Also, in order to compromise between the fault-location accuracy and the allocation costs, an optimal monitor-allocation algorithm is developed for determining the Pareto-optimal set of meter placements that have the minimal number of monitors to satisfy the requirements of fault-location accuracy. The proposed optimal allocation algorithm and the two types of fault-location approaches are validated on a modified IEEE 123-node test feeder using Matlab and Simulink.

Chapter 12 - Utility practices on fault location

The addition of distributed generation sources into conventional distribution networks results in several technical challenges for successful operation of distribution network. As far as physical integration is concerned, finding the exact location of fault is a key issue. The coordination between the protection devices existing in the distribution network gets disrupted due to presence of distributed generation (DG). Therefore existing fault location techniques for distribution system will not work properly with penetration of DG. Therefore new fault location schemes for distribution networks with distributed generations (DG) have been developed in the recent times, but there are still problems whose solution needs to be found out. This paper investigates the issues and current state regarding fault location in distribution network with DG. A comparative analysis is carried out in which the merit and demerit of each technique is assessed and some conclusion and suggestion for fault location in distribution system with DG is put forward.

The 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.