Short-circuit Location Research Articles

Разработка и исследование имитационной модели мультикамерного разрядника для грозозащитного троса

Optical fiber overhead ground wire (OPGW) is an effective solution for laying mainline digital communications along high-voltage power lines. It allows you to use the existing infrastructure of the power grid and ensure the transfer of a large amount of data. The flow of lightning currents and short-circuit currents can cause a violation of the thermal resistance of the fiber and a deterioration of its performance. When the OPGW is insulated through an insulator shunted by a spark gap, during operation it is possible to change the distance in the discharge gap due to the displacement of the electrodes in the plane. Also, when the short circuit location is close, multiple overlaps will occur and as a result, short circuit current will flow through the OPGW. Thus, the article considers the possibility to use a device with a multielectrode system developed on the principle of a multichamber spark gap as a replacement of the spark gap to increase the reliability of the unit with an isolated OPGW suspension. Modeling of the device has been carried out in the ANSYS Maxwell software package, the mathematical apparatus of which is based on the use of Maxwell's differential equations and the finite element method, which allows performing numerical modeling with sufficiently high accuracy. A simulation model of a multichamber spark gap has been developed in the ANSYS Maxwell software package and calculations of electrical characteristics have been performed. For the electrode system of a multi-chamber arrester, an uneven distribution of the applied voltage across the spark discharge gaps of the chambers is determined. It is shown that when a voltage is applied to a spark gap, the highest electric field strength occurs between the first and second electrodes, and then a cascade of discharge gaps occurs, which provides the required low discharge voltages of the spark gap as a whole. The developed simplified simulation model of a multi-chamber arrester has shown all the necessary conditions for cascade imaging of the voltage distribution and the electric-field strength of various electrode options. Based on the research conducted electrodes geometry is identified for smart prototype development and ongoing multi-chamber arrester research.

Detection and location of inter-turn short-circuit in a PMSM based on square of negative sequence current vector modulus

Detection and location of inter-turn short-circuit in a PMSM based on square of negative sequence current vector modulus

Research on internal short circuit detection method for lithium-ion batteries based on battery expansion characteristics

Short circuits are a major contributor to thermal runaway in lithium-ion batteries, but present detection techniques cannot distinguish different forms of short circuits. Therefore, the paper provides a detection method for internal short circuits (ISCs) based on coupled mechanical stress that can determine the type of short circuit. Firstly, cathode-anode (Ca-An) short-circuit batteries with a controllable triggering time and measurable internal temperature and electrode potential are designed. Secondly, the performance evolution of fault batteries under coupled mechanical stress conditions is investigated, along with the impact of faults on the battery's safety performance. Additionally, the influence of battery expansion characteristics on the contact pressure at the short circuit location and the correlation between short circuit resistance and mechanical stress are analyzed. The results show, except for self-discharge, no significant differences between Ca-An short-circuit and normal batteries, and there are no mutable features observed, but the faults can exacerbate internal-external temperature differences during charging. The different reasons for thermal runaway during sustained pressurization between short-circuit and normal batteries are revealed. Finally, a method for detecting ISC based on the differences in short-circuit resistance at different states of charge is proposed. Overall, the paper provides a basis for fault classification in lithium-ion batteries.

Method for determining the locations of power cable damage

Problem. Existing methods for remotely detecting cable damage locations, except in the case of cable breakage, have a common drawback. They are unable to accurately separate the cable core resistance from the transient resistance at the short-circuit location, leading to low accuracy in fault detection. The posterior transient resistance at the short-circuit location can vary widely, depending on when the repair crew arrives. Goal. The goal of this study is to propose a method for identifying the location of "floating breakdown" cable damage. Methodology. The method involves using short-circuit indicators to determine the type and area(s) of the short circuit. The UNI-TUT255A device, a current clamp type, is then installed on the damaged cable core. The Imax option with memory is set, and the cable is switched on at the rated voltage. By comparing the recorded shock current value with the values obtained from a short-circuit model of the cable in MATLAB, the location of the damage along the length of the cable is determined. The point where the shock current value of the model matches the recorded value corresponds to the location of the short circuit. Originality. The proposed method addresses the challenge of locating faults in power cables, specifically those of the "floating breakdown" type. This type of cable damage, which occurs when the cable is accidentally disconnected during a short circuit, poses difficulties in detection, as traditional methods may show normal readings. The method presented in this study overcomes these limitations and provides a practical solution for identifying "floating breakdown" faults. Practical value. The results obtained from this method allow for the accurate detection of faults at the nominal voltage, without the need for burning the cable. This reduces the probability of additional damage caused by overvoltage. Furthermore, the method requires only one operator to carry the necessary equipment, eliminating the need for transport with powerful burning installations typically used in traditional methods.

Operational determination of the point of a short circuit in power lines

RELEVANCE. An urgent task is to improve the reliability and quality of power supply. Very often, failures in operation are caused by damage to overhead and cable lines. Traditionally, a fairly large number of violations occur in the share of electrical distribution networks. For the reliable functioning of power systems and uninterrupted power supply to consumers, it is necessary to identify and eliminate faults in a short time to minimize damage. Thus, a method for efficient, accurate and reliable fault location is needed for both utility companies and consumers. To solve this problem, it is necessary to quickly obtain information about the state of the distribution eclectic network. THE PURPOSE. Reducing the time to search for a fault location in electrical networks, reducing damage from downtime for undersupply of electricity by analyzing existing methods for determining the location of faults on a power transmission line and developing a method for its prompt detection in electrical networks. METHODS. The basis of this method is a preliminary theoretical calculation of short-circuit currents in various sections of a power line. Based on the values obtained as a result of the calculation, the measured values of the short-circuit currents are compared with these values, on the basis of which the location of the line damage is determined. An algorithm for searching the left and right boundaries of the short-circuit current value in an ordered array of statistical data has been developed. RESULTS. A method for quickly determining the location of a short circuit is proposed, which is based on the use of a data array of theoretically calculated short circuit currents. The presented algorithm is able to accurately determine the coordinates of the short circuit in electrical networks. CONCLUSION. The proposed method for determining the location of damage to the power line allows you to increase the efficiency of determining the point of a short circuit and thereby reduce the time to eliminate the accident, and therefore, economic losses from undersupply of electricity.The basis of this method is a preliminary theoretical calculation of short-circuit currents in various sections of a power line. Due to the subsequent comparison of the measured values of short-circuit currents with the values of the calculated values, the location of the damage to the power line is determined. The presented algorithm is designed to accurately determine thecoordinates of the short circuit location, which can significantly reduce the search time and improve the accuracy of determining the fault location in the range from 100 to 150 m, regardless of the length of the power line, which significantly reduces the time to search for damage at the same time as solving the problem of reducing downtime , as well as minimizing damage both for guaranteeing suppliers represented by electric grid companies, and for consumers represented by industrial and agricultural enterprises.

Study on discharge characteristics of pulsed power module under the condition of discharge short circuit fault

Efficiency and safety are key factors that must be emphasized in pulsed power applications. The discharge characteristics of pulsed power supply directly determine the performance of the railgun. This paper conducts a research on short-circuit faults in transmission coaxial cables of pulsed power supply. In order to study the effect of short-circuit fault on the discharge characteristics of pulsed power supply and system efficiency,a pulse-forming network with cable short-circuit failure and dynamic railgun model are established in the paper. The effect of short-circuit fault on peak current is discussed by simulation. The results show that the short-circuit fault currents are all higher than the currents under normal conditions, and the closer the short-circuit location is to the power supply side, the higher the peak value of current is. In some extreme case, the peak fault current exceeds 1.5 times the normal, which requires consideration of short-circuit fault protection measures, such as the addition of a DC circuit breakers.

Study of Short Circuit and Inrush Current Impact on the Current-Limiting Reactor Operation in an Industrial Grid

Current-limiting reactors are widely used in industrial electrical grids to reduce the current amplitude in the equipment and stabilize the voltage on the busbar during short circuits. Their application is distinguished by high technical and economic efficiency. However, mechanical damage to the reactors has been observed within extensive industrial grids with many induction motors and internal synchronous generators. The article analyses a case study of the reactor damage in the true industrial grid during a short circuit. An analysis of the damaged reactor’s previous operation had shown that there was a weakening of the fastenings in the reactor design, caused by the repeated starting currents of the grid motors and generators. A study of grid transients during short circuits was carried out by Matlab/Simulink software. The simulation results showed that the reactor could be damaged by a critical peak current in an unfavourable combination of the grid configuration and the short circuit location. The results of the study prove that, for industrial networks containing powerful induction motors and internal synchronous generators, the standardized procedure for selecting current-limiting reactors should additionally consider such factors as the localization in the grid, the effect of equipment-starting currents and possible grid configurations.

Random Forest-Based Online Detection and Location of Internal Short Circuits in Lithium Battery Energy Storage Systems With Limited Number of Sensors

Random Forest-Based Online Detection and Location of Internal Short Circuits in Lithium Battery Energy Storage Systems With Limited Number of Sensors

Identification of electrode short circuits during the electrolytic refining of copper based on heat radiation

This study is aimed at improving the efficiency of monitoring and automated control over the technological state of electrolytic cells during copper refining using the recognition and identification of short circuits between the electrodes. Experimental works were performed on a laboratory bench consisting of two cells connected in series to the electrical circuit. The method of detecting short circuits is based on measuring infrared radiation using a scanning thermal imager (Оptris PI 400i / PI 450i) for determining areas with elevated temperatures of electrode and electrolyte surfaces. A short-circuit detection algorithm was developed and tested in MATLAB environment using the Image Processing Toolbox MATLAB functions. The proposed method for recognizing and identifying short circuits between the electrodes of an electrolytic cell is based on using a scanning digital thermal imager. This method allows a comprehensive assessment of the contact area, determination of both the start time of a short circuit and the degree of electrode heating in the short-circuit zone, as well as establishment of temperature values in all areas, including the electrolyte temperature in the entire volume of the cell. An algorithm for searching for short-circuit locations in an electrolytic cell is proposed. This algorithm involves the collection of data and its comparison for adjusting the inter-electrode distance, ensuring a stable energy mode for the entire electrolytic line, and determining the exact position of each cathode in the cell using the threshold processing of infrared images obtained by a thermal imager. It was established that timely identification of short circuit locations in the electrolytic bath (since the onset of a contact between the electrodes), as well as recording of the growth rates of a dendritic coalescence area and electrolyte temperature, ensure timely elimination of technological disturbances during the operation of electrolytic baths. Thus, the developed method of short circuit identification for comprehensive determination and recognition of the technological state of an electrolytic cell during the electrolytic refining of copper can be used to reach a stable energy mode with minimum deviations in the process temperature.

CALCULATION OF SHORT-CIRCUIT CURRENTS IN MARINE ELECTRIC POWER SYSTEMS WITH DIRECT CURRENT POWER DISTRIBUTION

A method for calculating shock short-circuit currents in marine electric power systems with direct current distribution of electricity is presented in the paper. These systems are widely used in shipbuilding. The calculation of short-circuit currents in such systems has a number of features related to the operating modes of these networks. In the systems with direct current electricity distribution, the generation and consumption of electricity is carried out on alternating current, while the distribution is carried out on direct current. The current standards for calculating short-circuit currents in DC and AC systems in this case cannot be used for a number of reasons. These standards do not consider specific supply sources of short-circuit points (short circuit) and variable rotational speed of valve generators in the various operating modes. AC electric motors (ED), when they are mains powered with DC power distribution via autonomous inverters, supply the short-circuit point on the DC side. Capacitor banks and accumulator batteries connected to a system with direct current electricity distribution are additional sources for the short circuit site supply. The elements of a methodology for calculating short-circuit currents in marine power plants with direct current electricity distribution, taking into account all operating modes and additional sources of short-circuit location recharge, are proposed in the paper. A method for determining the maximum value of the shock current at the short circuit design point of the ship’s electric power system is proposed.

On the Effects of Lamination Artificial Faults in a 15 kVA Three-Phase Transformer Core

Cutting and punching of the steel used in power transformer core may cause edge burrs. This, along with the degradation of the lamination insulation, can lead to interlaminar short circuits. Analysing these faults helps understanding their effect on the transformer reliability and performance. In this light, the actual paper aims to experimentally simulate and analyse both faults using a 15 kVA three phase power transformer. Effects produced from both selected faults are experimentally investigated in this paper where different scenarios are considered such as the area of the affected regions and the number of short-circuited laminations. Various flux densities are considered ranging from 0.5 to 1.8 T. Of interest, the current at no load is recorded and the test is repeated for any given scenario. The obtained results are presented and discussed to study the effect of each fault on the transformer performance. Overall, the transformer current increases with the number of short-circuits between laminations for both faults. This increase is related to the flux density, which is dependent and sensitive to the short circuit location. Such findings represent a good indication of the severity of short circuits relative to their position in the transformer core, and can be exploited to discuss the power losses in the transformer core.

Determination of short circuit location in the electric railway traction

This article discusses the problem of improving the accuracy of determining the location of a short circuit in the AC railways traction networks. Finding a short circuit can take several hours. An urgent task is reducing the time to search for a fault location. The purpose of the study is to develop a method that increases the accuracy of determining the location of a short circuit in AC traction networks. The method is based on computer modeling of inhomogeneities in the structure of the traction network and the arc. The proposed method makes it possible to take into account the arc resistance. The method was tested on the traction network active section. The error of the method is 200-300 meters. The method can find practical application in the work of dispatchers.

Internal Short Circuit Mechanism By Metallic Contaminant in an All-Solid-State Battery with Sulfide Electrolyte

In LIBs, the metallic contaminants in the cathode are ionized and dissolve into the electrolyte during charging due to the oxidation-reduction potential, and the dissolved cations move and deposit on the anode as metal by the reduction. It is known that the repetition of this phenomenon causes the formation of needle-like metals resulting in the penetration through the separator and it may cause internal short circuit besides capacity degradation. Since slight voltage-drop occurs in the initial stage of this phenomenon, the defective batteries can be eliminated in the aging process. On the other hand, internal short circuit by metallic contaminant in all-solid-state batteries (ASSBs) has not been investigated well. In order to confirm this phenomenon in ASSBs, contaminant metals (Al, Cu, Fe, Ni, SUS) particles were intentionally added to the cathode and the cycle tests were carried out at 60℃. In the tests, internal short-circuit was detected only with the battery containing the Cu contaminant at 15 cycles. The location of short-circuit in the battery was visualized by magnetic imaging for the elucidation of the mechanism, then the battery was disassembled and the chemical state of Cu was measured by XAFS. It was found that Cu was present mainly as CuS in the solid electrolyte (SE) layer and the anode at the spot of short-circuit as well as the cathode, while CuS, having the structure of covellite in nature, is conductive.1 Thus, the short-circuit probably took place by the connection of the cathode and the anode via CuS through the SE layer. The movement of Cu in the battery during charging and discharging was monitored by in-situ SEM-EDX. After charging, Cu in the cathode moved to the SE layer whose Cu density decreased after the discharging, suggesting that Cu moves as cations.AcknowledgmentsThis study was carried out in SOLiD-EV project supported by NEDO (New Energy and Industrial Technology Development Organization).

Impact of DG on short circuit current detected by protection

DG (distributed generation) access causes the change of current detected by the protection, and then affects the sensitivity of the original protection. In order to solve the problem, the influences of DG capacity, DG access location and short-circuit location on short circuit current are analysed in this paper. When the DG capacity and grid-connected position remain unchanged, the unit current method is used to solve the short-circuit current by solving the transfer impedance. The relationship between the change of short circuit position and the impact degree of DG is discussed in detail, and the calculation formula of extreme point is derived. When the DG capacity and short circuit location remain unchanged, the impact of DG grid-connected position on the upstream and downstream current is analysed. The characteristic curve of the impact of DG position change on protection current detection is given, and the impact of DG grid-connected position on protection sensitivity is explained clearly. The conclusion provides an important reference for the selection of DG grid-connected position and the calculation of relay protection in distribution network with DG.

The use of energy routers to improve reliability of power supply to non-traction consumers

The purpose of the studies presented in the article was to determine the effectiveness of the use of energy routers (ER) in railway power supply systems to increase the uninterrupted power supply to non-traction consumers, reduce unbalance and nonsinusoidality, and reduce voltage dips in emergency modes. The research was carried out by means of computer modeling using the Matlab software system based on the developed models of power supply systems (PSS) equipped with ER with energy storage devices. The results obtained show that in standard circuits of PSS for linear consumers with short circuits in the supply network, voltage dips occur, the depth of which reaches 100%. The use of an ER and an energy storage device connected to DC buses allows maintaining voltage at consumer clamps near the nominal value in case of short circuits in the 10 kV feed line and 25 kV overhead contact system. The ER significantly limits the recharge of the short circuit location from the power storage. In addition, on the basis of the ER it is possible to provide the normative quality of electricity considering voltage deviations, asymmetry and harmonic distortions on the 0.4 kV buses of the substation that feeds non-traction consumers.

Simulation of criteria for selection of remote protection settings with remote starting in lines with distributed sources

The article presents the conditions of coordination of adjacent remote protections with remote start-up, considering the peculiarities of parameters, operating modes and operating conditions of partitioned branched distribution lines. The influence of parameters and modes of operation of such lines on the technical characteristics of these protections, in particular, on the range of control settings for resistance and operating time at the end of the range and the requirements for the linearity of time characteristics. It is recommended to use the results of the conducted research for adjustment of remote protections of partitioned lines with sources of distributed generation. In order to ensure the selective action of protection in different modes of operation of the lines and the convenience of choosing the settings of operation, the time characteristic of the protection must be linear. In addition, the linearity of the protection time characteristic allows the operation time value to be used to determine the distance to the short circuit location. Due to the need to debug the protection by the time of operation from the operation of the arresters and from burnout of the fusible insert fuses soldering in the event of a short circuit directly behind the fuse, the initial duration of protection should be 0.25…0.40 s.

Study on sensitivity and selectivity of three-stage current protection in distribution network with distributed generation

The connection of DG (Distributed Generation) changes the topology of distribution network, which will lead to the change of current detected by relay protection, and the sensitivity and scope of protection will be affected. On the basis of introducing the setting calculation principle of three-stage current protection in distribution network, taking a 10kV distribution network with DG as a model, the influence of DG capacity change on the selectivity and sensitivity of three-stage current protection is discussed in detail when short circuit occurs in different locations such as downstream, adjacent and upstream lines. The corresponding restrictive factors are analyzed and the influence degree of DG access on the original protection is given after comprehensive comparison. It is concluded that comparing different short circuit locations, DG has the most serious impact on the stage-I selectivity of downstream protection when the short circuit occurs at DG downstream line. The conclusions in this paper are of great value to ensure the reliability of power supply of distribution network when a large number of DGs are connected to the grid.

Data‐driven short‐circuit detection and location in microgrids using micro‐synchrophasors

Fault detection and location is a challenging issue in microgrid protection, which is increasingly more complex in the presence of distributed generators based on renewable energy, due to their inherent intermittency. In this context, a novel data-driven approach for fault detection and location in microgrids is proposed, by using graph theory representation and micro-synchrophasors also known as μ PMUs. This proposal adopts the conviction to provide an accurate fault location even under variations in short-circuit levels caused by the intermittency of distributed generators. This is in sharp contrast with traditional short-circuit rating-based methods, which are not always advisable due to the intermittent nature of power sources. This work proposes the use of a modelling specification in terms of equilibrium equations, that can reveal not only the underlying physical laws of the netowork, but also the occurrence and location of short circuits based on phasor data. The intermittency of distributed generation is modelled in the proposed approach, which permits to yield trustworthy information either distributed generators are involved in a fault or not. As a consequence, the fault location errors are significantly reduced during the fault location process. The theoretical findings of this proposal are validated via simulation results and experiments using commercial micro-synchrophasors and hardware-in-the-loop emulation of a realistic microgrid.

Adaptive Coordination of Damping Controllers for Enhanced Power System Stability

This paper introduces the concept of adaptive coordination of damping controllers for enhancing power system stability. The coordination uses phasor measurement units (PMUs) to adapt to different disturbances by selecting the switching status (on/off) of damping controllers that minimizes an energy-based dynamic performance measure. This dynamic performance measure, referred to as total action (TA), uses a physical interpretation of excited modes rather than fixed targeted modes as in the traditional damping control design. The coordination is formulated as a binary integer programming problem, which is solved by using the total action sensitivity (TAS). The concept of oscillation energy and the implementation of the adaptive coordination scheme is tested in the western North America power system (wNAPS). The results show that the proposed adaptive control scheme can improve oscillation damping for different short-circuit locations even in the presence of large communication delays.

Detection and classification of landmines using UWB antenna system and ANN analysis

Background: The problem of detecting underground objects is found in many areas of human activity in the modern world, for example, a quick survey of the territory for the presence of underground utilities for earthworks, finding the location of grounding structures, cable breakage or short circuit, remote sensing for detecting and mapping of archaeological objects. The issue of humanitarian demining in Donetsk and Lugansk regions is also important in Ukraine. The latest ground surveying devices, such as ultrawideband subsurface radar, have already come to the aid for military sappers in developed countries to make the demining process safer. Objectives: The goal of this work is to improve the recognition of subsurface objects by using an artificial neural network (ANN) for signal processing, to test the influence of interference in signals coming from ultrawideband antenna system on the reliability of determining the object in the observation area, its type and distance to subsurface radar. Materials and methods: In this work, the ANN method is used to recognize the hidden objects by ultrawideband subsurface radar. The process of electromagnetic field propagation is simulated by finite time difference method (FDTD). Neural network testing is performed by adding Gaussian noise of different levels in the input signal. Simulation of the problem is performed 1000 times to exclude the randomness of recognition for different realizations of a noise. Results: Histograms of objects recognition for two types of mines and six types of cans were obtained. A large set of false objects for neural network training gave good results in the detection of antipersonnel mines, which was reflected in the excellent stability of determining the position and type of object, even in the presence of interference with a high signal-to-noise ratio. Conclusions: The problem of subsurface survey can be solved by using a fully connected neural network with five hidden layers of neurons. It has been determined that the use of artificial intelligence gives good results in the recognition of underground objects, if a high-quality learning data set for ANN will be prepared. Satisfactory stability of noisy signal operation is shown, which gives prospects for further testing of the developed method in application to a subsurface radar in the conditions of a real experiment.