Series Faults Research Articles

Design of fault arc detection device based on STM32

The detection of the load current signal is one of the effective methods for judging whether an arc fault occurs in the low-voltage distribution line; according to the national standard GB/T 31143-2014 General Requirements for Arc Fault Protection Devices (AFDD), the analog series fault arc is built. The experimental platform studies the characteristics of the current waveform when the fault arc occurs. The db4 wavelet function is used as the wavelet basis function to decompose and reconstruct the current waveform after noise reduction, and extract the wavelet high-frequency component, calculate the periodic variance value of the wavelet high-frequency component, and detect the arc fault according to this value; The feasibility and effectiveness of the detection algorithm are verified. The arc fault detection algorithm is transplanted to the STM32 platform, and the fault arc detection device based on STM32 is designed. The device can realize the functions of current signal acquisition, data processing and series arc fault detection and recognition. Experiments with resistive loads, LED light, vacuum cleaners and microwave ovens have shown that the device can detect series arc faults with high reliability and will not cause false positives without generating fault arcs.

통계적 기계학습법을 적용한 플랜트 공정 장비의 시계열 데이터 분석 및 고장 상태 진단

통계적 기계학습법을 적용한 플랜트 공정 장비의 시계열 데이터 분석 및 고장 상태 진단

Fault Detection and Location of Photovoltaic Based DC Microgrid Using Differential Protection Strategy

A new differential current-based fast fault detection and location scheme for multiple Photovoltaic-based dc microgrid is proposed in this paper. A multiterminal dc (MTDC) distribution network is an effective solution for present grid scenario, where local distribution is incorporated primarily by power electronics based dc loads. PV systems with auxiliary power sources and local loads are used for MTDC connection, especially when ac utility grid is integrated with it by voltage source converters. Pole to pole and pole to ground faults are basically considered as dc distribution network hazards. As PV is connected through dc cable, high resistive dc arc fault is also studied in present literature. The proposed PV system is considered with arc-fault circuit interrupters as backup protection and is used to detect arcing series fault. Fast acting dc switching is considered for proposed differential current-based unit protection. A discrete frame differential current solution is considered to classify the fault type by modified cumulative sum average approach. By calculating unknown dc cable resistance accurately by non-iterative Moore-Penrose pseudo inverse technique, the fault distance is calculated. TMS320C6713 DSP based test-bench is used for verification of the scheme.

Weighted time series fault diagnosis based on a stacked sparse autoencoder

Most statistical analysis technologies use detection thresholds for fault diagnosis, which often cannot effectively characterize some specific faults in a statistical manner. However, the details and small changes in the faults can be exploited by deep learning‐based feature representation. In this paper, we present a weighted time series fault diagnosis method to learn the deep correlations of faults and reduce the loss of fault information. Our model includes 2 key novel properties: (1) It can learn high‐level abstract features of faults and the underlying fault patterns, which is particularly efficient for detecting incipient faults; (2) a mathematical framework of stacked sparse autoencoder‐based fault diagnosis, with capabilities of multiple nonlinear mapping and complex function approximation, is presented. The monitoring performance was compared with multivariate statistical methods and conventional artificial intelligence methods on the Tennessee Eastman process data set, which is a well‐known chemical industrial benchmark. The experimental results showed its performance gain over existing methods, especially for incipient faults that are difficult to detect with traditional technologies.

Double‐ended technique for distinguishing series faults from shunt faults on transmission lines using the sequential components of impedance

This study describes a new double-ended technique for distinguishing series faults from shunt faults. The proposed method is based on the sequential components of impedance. Using the local and remote positive-sequence voltage and the local positive-sequence current, a new value is introduced and utilised to distinguish series faults, mostly known as broken conductors, from shunt faults. As the proposed method utilises a double-ended technique, it will act when the necessary information of the remote end of the line is received. By detecting the broken conductor condition within a few power cycles, this method can trip the circuit breakers at both line ends before any conductor contacts the earth, and thus can avoid safety problems and damages to the electrical equipment. Moreover, it can also classify which type of broken conductor (one-phase or two-phase) condition has occurred. The excellent performance of the proposed method is demonstrated by extensive simulation studies with MATLAB/Simulink.

Condition Monitoring of Instrumentation Cable Splices Using Kalman Filtering

A linear chirp reflectometry with chirp stretching processing is used to detect and to locate low-voltage control and instrumentation cable splices and fault. Time delay information in the reflected signal is transformed to the instantaneous beat angular frequency by stretching process and the instantaneous beat angular frequency is estimated by Kalman smoother in order to obtain the high resolution time-frequency spectrum of the nonstationary signal. Based on the estimated instantaneous beat angular frequency, the magnitude and phase difference of the reflection coefficient are estimated by Kalman filtering. To verify the performance of the proposed method, comparative experiments are conducted to detect and to locate the splice under different conditions in comparison with traditional time-domain reflectometry method and the proposed method. In addition, to demonstrate the efficacy of the proposed method, the experiments are carried out for the assessment of state of the shunt and serial faults on cable under test. The location and reflection coefficient of a nominal, water submerged, an opened splice, shunt fault and serial fault (10 Ω, 30 Ω, 50 Ω, 70 Ω, 90 Ω, 1 kΩ) are estimated by the proposed method. The proposed method exhibits advantages in that it uses the pulse compression to improve the range resolution and SNR of reflectometer simultaneously, and the proposed technique can accurately assess the state of the fault, which is closed to short fault or open fault.

Development of Fault Detector for Series Arc Fault in Low Voltage DC Distribution System using Wavelet Singular Value Decomposition and State Diagram

It is well known that series arc faults in Low Voltage DC (LVDC) distribution system occur at unintended points of discontinuity within an electrical circuit. These faults can make circuit breakers not respond timely due to low fault current. It, therefore, is needed to detect the series fault for protecting circuits from electrical fires. This paper proposes a novel scheme to detect the series arc fault using Wavelet Singular Value Decomposition (WSVD) and state diagram. In this paper, the fault detector developed is designed by using three criterion factors based on the RMS value of Singular value of Approximation (SA), Sum of the absolute value of Detail (SD), and state diagram. LVDC distribution system including AC/DC and DC/DC converter is modeled to verify the proposed scheme using ElectroMagnetic Transient Program (EMTP) software. EMTP/MODELS is also utilized to implement the series arc model and WSVD. Simulation results according to various conditions clearly show the effectiveness of the proposed scheme.

Fuzzy Inference System Approach for Locating Series, Shunt, and Simultaneous Series-Shunt Faults in Double Circuit Transmission Lines.

Many schemes are reported for shunt fault location estimation, but fault location estimation of series or open conductor faults has not been dealt with so far. The existing numerical relays only detect the open conductor (series) fault and give the indication of the faulty phase(s), but they are unable to locate the series fault. The repair crew needs to patrol the complete line to find the location of series fault. In this paper fuzzy based fault detection/classification and location schemes in time domain are proposed for both series faults, shunt faults, and simultaneous series and shunt faults. The fault simulation studies and fault location algorithm have been developed using Matlab/Simulink. Synchronized phasors of voltage and current signals of both the ends of the line have been used as input to the proposed fuzzy based fault location scheme. Percentage of error in location of series fault is within 1% and shunt fault is 5% for all the tested fault cases. Validation of percentage of error in location estimation is done using Chi square test with both 1% and 5% level of significance.

The Analysis of Faults Detection Software Based on Improved Neural Network Algorithm

The large-scale software is consisted of the components which are quite different. The detection accuracy of the traditional faults detection methods for the large-scale component software is not satisfactory. This paper proposes a large-scale software faults detection methods based on improved neural network combining the features of the large-scale software by computing the stable probability and building the neural network faults detection models. The proposed method can analyze the serial faults of the large-scale software to determine the positions of the faults. The experiment and simulation results show that the improved method for large-scale software fault detection can greatly improve the accuracy.

Research on Vibration Signal Feature Extraction Method to the Wind Turbine Generator

Aiming at the safe operation of the wind turbine, a feature extraction method of vibration signal based on the principle of blind source separation was proposed. Blind source and the current state of fault signal was separated and predicated by Using historical data of wind turbine vibration signal as the observation noise, and then fault diagnosis signal mechanical operation was analyzed, the HMM/SVM series fault diagnosis models structure was proposed. By calculating the matching degree of unknown signal and wind power equipment in the state using HMM, the features for SVM was formed to achieve the finally discriminant. The experimental results showed that the fault diagnosis method can precisely and effectively complete the wind power equipment, higher than pure HMM or SVM diagnostic accuracy.

A DC Arc Model for Series Faults in Low Voltage Microgrids

This paper presents a dc arc model to simplify the study of a critical issue in dc microgrids: series faults. The model is derived from a hyperbolic approximation of observed arc voltage and current patterns, which permit analyzing the arc in terms of its resistance, power, energy, and quenching condition. Recent faults staged by the authors on a dc microgrid yielded enough data to develop an arc model for three fault types: constant-gap speed, fixed-gap distance, and accelerated gap. The results in this paper compare experimental and simulation results for the three fault types. It is concluded that because the instantaneous voltage, current, power, and energy waveforms produced by the model agree well with experimental results, the model is suitable for transient simulations.

Guest Editorial Special Section on Microgrids

Despite the significant research efforts devoted to the microgrid and smart grid areas, numerous problems related to real world implementations still remain unsolved. The present special issue was announced with the objective of addressing and disseminating state-of-the-art R&D results on microgrids to bring together researchers from both academia and industry with the goal of fostering interactions among stakeholders. In response, 190 two-page extended abstracts were received and considered for the first round of reviews. Authors of about 60 selected abstracts were then invited to submit the full papers in the second round and out of them 27 high-quality manuscripts were ultimately approved and included in this special issue. These papers are organized according to the following four topics: 1) Microgrid dynamic performance, control/operational strategies, and voltage/frequency regulation. Here, 14 papers deal with the dynamic modeling and performance ofmicrogrid or its building blocks and propose appropriate control/operational strategies or voltage/frequency regulation approaches. 2) Reliability and power quality aspects of microgrids, where seven papers about the microgrid reliability assessment techniques, impact of distributed energy resources on microgrid reliability indices, and the microgrid power quality analysis are presented. 3) Fault modeling and protection schemes. This section consists of four papers focusing on series fault modeling in dc microgrids, overvoltage protection of photovoltaic generators, and protection schemes tailored for the microgrid operational characteristics. 4) Others: Two practical papers about the impact of microgrids on the planning of the medium-voltage distribution networks and characterization of the Vanadium Redox battery are presented.

Ore Fluid Properties and Sources from Quartz-Associated Gold at the Betze-Post Carlin-Type Gold Deposit, Nevada, United States

Quartz at the Betze-Post deposit, the largest Carlin-type gold system in the world, was examined to better understand ore fluid properties and sources that generated Carlin-type gold deposits. Detailed petrography and paragenesis investigations distinguished textural relationships, luminescence, various generations of quartz, and fluid inclusion populations; microthermometry, chemical analyses of quartz, and in situ and conventional oxygen isotope analyses of quartz provided information about hydrothermal fluid conditions as well as fluid sources and ore formation processes. Pre-, syn-, late-, and post-ore stages of quartz were distinguished during petrographic studies and confirmed by cathodoluminescence analyses. Ore-stage jasperoid and late-ore drusy quartz are spatially associated with Au-bearing pyrite; both lack luminescence. Two generations of post-ore drusy quartz overgrew ore and late-ore quartz and exhibit bright and multiply zoned luminescence. Electron probe microanalyses determined that nonluminescing ore and late-ore quartz have elevated concentrations of Al, in contrast to post-ore luminescent quartz that contains low trace element concentrations. Fluid inclusion microthermometry determined that ore-stage fluids had low salinities, generally <5 wt % NaCl equiv, and were trapped at 180° to 240°C. The δ 18O values, calculated for inclusion fluids and determined for quartz using in situ ion probe and conventional analyses, indicate that the isotopic composition of hydrothermal fluids became 18O depleted with time, from the ore stage through the late-ore stage to the post-ore stage. The δ 18O composition of each stage of quartz also varies spatially across the Betze-Post deposit, and δ 18OVSMOW values of ore-, late-ore, and post-ore stage quartz became more depleted with increasing distance from the master Post fault. These patterns are interpreted to result from increasing dilution of the 18O-enriched ore fluid by unevolved meteoric fluids over time and with increased ore fluid transport distance to the west, away from the Post fault, the master fault that transmitted hydrothermal fluids to the deposit. Oxygen isotope results are consistent with a low fluid/rock ratio during upward transport of the ore fluid via the Post fault. Below the deposit, some ore fluids were diverted into the JB Series faults, associated with the Betze ore zones, and the Shalosky fault, associated with the Screamer ore zone in the western part of the deposit. Ore fluids were increasingly diluted by meteoric fluids with distance as ore fluids traveled away from the Post fault and over time as different stages of quartz precipitated. Acidic, 180° to 240°C ore fluids accessed the level of the deposits where they reacted with the Devonian Popovich Formation and precipitated nonluminescing, Al-enriched ore-stage jasperoid and late-ore drusy quartz, along with Au and trace element-rich pyrite. Fluid-rock reaction, dissolution, and replacement of silty carbonate host rocks may have produced Al that substituted for Si in non-luminescing jasperoid and late-ore stage quartz. As the hydrothermal ore system began to cool and collapse, late-ore drusy quartz and realgar precipitated in open space as ore-stage pyrite precipitation declined. The hydrothermal system collapsed with meteoric water flooding; post-ore minerals, including luminescent, Al-poor post-ore drusy quartz and later calcite and barite, precipitated either from latest Carlin-related fluids, neutralized by infiltration of meteoric waters, or as part of a later, separate hydrothermal event.

General Model of n Degree Simultaneous Electrical Faults and Calculating them by PC

This work studies double electrical faults (at n nodes simultaneously) in electrical networks and concludes the general mathematical model to analyze electrical systems during double faults occurred in electrical power systems using matrix model of the nodes admittance equations. the research work also explains general mathematical model by which symmetric and asymmetric electrical faults for all types of shunt and series faults and doubled faults are calculated (i.e faults occurring simultaneously in more than one node) As well as developing the required calculations algorithm of the investigated systems and propose solution represented in calculating any double electrical fault including its long and wide components altogether at any node using general algorithm without the need to go back to the beginning and loading the program again when the two nodes place of the fault changes, or faults type changes. A general model with matrix formula for equations of symmetric volts components in faults nodes and the ultimate conditions of each fault's type of doubled faults have been set, in order to obtain symmetric components values of faults currents in doubled faults nodes where fault is being studied

Fault current limiter using a series impedance combined with bus sectionalizing circuit breaker

The necessity and procedure for application of series fault current limiter (FCL) composed to bus sectionalizing in power network of IRAN have been discussed. In this regard, all of the high voltage substations in the power network of IRAN were evaluated in point of view of the fault current amplitude. The short circuit analysis of the power network was done based on the actual and future network specifications which have been designed and published by Iran Generation Transmission & Distribution Company in 2005. The overall results of this analysis and the detail data of using FCL together bus sectionalizing for two of the most important high voltage substations of Iran are presented. This method allows decreasing of 27% in fault current amplitude. The economical observation shows this method can be profitable if high voltage substation contains more than four feeders.

A Generalized Methodology Based on Symmetrical Components for Multiple-fault Calculation in Power Systems

This article presents an efficient computational method to solve the problem of simultaneous multiple faults in power systems, using a conventional symmetrical component formulation. The methodology made possible the development of a programming routine, which takes into account a generic set of boundary conditions for almost any type of fault or combination of faults that can occur simultaneously, involving any number of phases. The program was tested with IEEE 14-, 57-, 118-, and 300-busbar benchmark systems facing up to ten simultaneous series and shunt faults. The results were satisfactorily tested against classical three-phase formulation solutions.

A neural networks-based negative selection algorithm in fault diagnosis

Inspired by the self/nonself discrimination theory of the natural immune system, the negative selection algorithm (NSA) is an emerging computational intelligence method. Generally, detectors in the original NSA are first generated in a random manner. However, those detectors matching the self samples are eliminated thereafter. The remaining detectors can therefore be employed to detect any anomaly. Unfortunately, conventional NSA detectors are not adaptive for dealing with time-varying circumstances. In the present paper, a novel neural networks-based NSA is proposed. The principle and structure of this NSA are discussed, and its training algorithm is derived. Taking advantage of efficient neural networks training, it has the distinguishing capability of adaptation, which is well suited for handling dynamical problems. A fault diagnosis scheme using the new NSA is also introduced. Two illustrative simulation examples of anomaly detection in chaotic time series and inner raceway fault diagnosis of motor bearings demonstrate the efficiency of the proposed neural networks-based NSA.

Triggered vacuum switch-based fault current limiter

A new type of fault current limiter (FCL) is proposed based on the triggered vacuum switch (TVS). The TVS-based FCL (TFCL) is mainly composed of a capacitor, a current-limiting reactor connected with the capacitor in series, and a TVS connected with the capacitor in parallel. With TVS at the "off" or "on" state, the whole TFCL behaves as conventional series compensation or fault current limitation, respectively. Compared with other types of FCLs, such as superconductivity, thyristor/GTO-based FCL, TFCL is distinguished by its characteristics, such as high capacity, loss free, and low price. The digital simulation and prototype experiment based on the LC resonant test circuit show that it is feasible to develop TFCL.

Generalized method for fault simulations in power systems

AbstractThis paper presents a new generalized method of modelling of any kind of shunt and series faults as single or simultaneous faults in arbitrary combination. The proposed approach can be used for conventional fault studies for the steady‐state model based on the nodal admittance representation as well as for fault simulations under transient conditions by means of the EMTP/ATP program. This method has been developed for phase coordinates but it is also suitable for any modal coordinates. The purpose of this paper is to show the incorporation of these fault conditions in the EMTP/ATP algorithm.

Computer Programs for Fault Studies Using Symmetrical Components in Undergraduate and Postgraduate Teaching

ABSTRACT The paper first reviews development of a digitial fault studies program for use in undergraduate and postgraduate teaching, highlighting aspects of program design. System data details: arrays containing details of system data: fault data; positive-, negative-, and zero-sequence network data; voltage arrays which store node voltages before and after the fault; corresponding current arrays; in addition to the file editor; routines for printing system data on screen or on paper; modifying system data; together with line data; and diagnostics are discussed for various shunt and series faults. Improved routines which employ complex impedances to represent generators, transformers and transmission lines on the more common PC's are explained. Phase voltages and currents for both shunt and series faults which illustrate the effect of the more common approximations such as neglecting system resistance or approximating complex impedance to constant angle impedance in shunt and series faults are made.