Arcing Fault Current Research Articles

Reliable Detection Method of Variable Series Arc Fault in Building Integrated Photovoltaic Systems Based on Nonstationary Time Series Analysis

Arc fault characteristics would be influenced by diverse system elements and operation levels in building integrated photovoltaic (BIPV) systems, which would challenge the arc fault detection. This paper aims at improving the detection reliability and speed by applying the time series analysis at feature and classification layers to reflect the random evolution process of arc fault current. According to the arc ignition method in UL1699B, arc fault signals are firstly sampled with a residential storage element and ten DC load elements at three voltage levels in BIPV systems. After evaluating time-frequency information with established indexes, variable and early arc fault are discovered to have no obvious current and harmonic indications due to strong system element noises, sensor precision and low arc energy. Then, sample entropy (SE) feature and gated recurrent unit (GRU) classifier are proposed to improve the detection performance through involving the nonstationary time series correlation of the arc fault current. An arc fault simulation platform is built to generate arc current with low signal-to-noise ratio (SNR), which proves the detection algorithm integrates multi-source information to grasp the appearance of new signal pattern. Next, constrained optimization problems are designed for both feature and classifier layers to achieve the most distinguishable arc fault and fault-like performance. With matched optimization methods, the modified SE and GRU method could improve the detection accuracy by an average of 21.08% after comparing with existing features and classifiers. Finally, hardware implementation results indicate a higher detection accuracy and less runtime of the proposed detection method.

Novel Approach for the Monitoring of Single Phase-to-Ground Fault Associated with Power Arc

This paper presents a general theoretical overview of a novel approach for the monitoring of the single phase-to-ground fault associated with power arc. Although several existing fault protection methods have been employed in order to resolve the power arcing faults associated with the single phase-to-ground faults, still ongoing research is trying to develop efficient methods that could help to suppress completely these dangerous power arcs from the systems. The operation of the protective relays and fuse systems is quite often questionable during recurrent failures in detecting the electric arcs as expected, especially during these arcs earlier events of formation. The most relevant reason causing these traditional faults protective switchgears seldom failures, limitations and drawbacks include essentially the varying amounts of resistance associated with these previously mentioned power arcs. Subsequently, the electric arcs related impedance and that of the power system tend to limit the arcing fault currents and voltages quantities at very low rates. Hence preventing the existing fault protective devices and switchgears to detect these arcs hazards, as long as the arcing fault related currents and voltages quantities are kept for a relatively long period of time below the nominal setting values of both the relays and the fuses systems. Subsequently, the entire power distribution system experiences the devastating effects of theses dangerous parasitic electric arcs hazards. However, in order to overcome the limitations, the disadvantages and the drawbacks of the above mentioned conventional fault protective devices, this paper divorces completely with the traditional practices in order to propose a radio measurement method.

Conversion of Intermittent Arc Fault Currents to Information Signals for Phase-to-Ground Fault Protection

Conversion of Intermittent Arc Fault Currents to Information Signals for Phase-to-Ground Fault Protection

Series arc fault identification based on complete ensemble empirical mode decomposition with adaptive noise and convolutional neural network

The effective identification of series arc faults is of considerable significance for preventing fires in residential buildings. Series arc fault currents and load currents have a similar waveform, and the fault features and nonfault features are superimposed on the current signal. Fault features are deeply hidden, making it difficult to identify them. This work proposes a method based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) preprocessing and a one-dimensional convolutional neural network (1DCNN). The CEEMDAN algorithm is used to decompose the collected current signals. Then, the intrinsic mode function (IMF) components with no representational significance are eliminated by calculating the Spearman correlation coefficient before inputting it into the 1DCNN. The experimental results showed that the accuracy of the method for the measured load is 99.3%. Compared with the method that directly uses original current signals as model inputs, the recognition accuracy of the algorithm was significantly improved. Therefore, the proposed algorithm can be used for series arc fault identification in residential building power distribution systems.

A Basic Assessment of Arc Flash in Low Voltage AC

The empirical model provided by the IEEE1584-2018 guide interpolates intermediate values of the average arc current, incident energy, and arc-flash boundary to determine final results, corrected by factors for enclosure size and arc current variation. Various kinds of software exist to assess the risk of arc flash complying with this model. It becomes relevant to have a physical understanding of the phenomenon, examining singularly the various parameters that affect it, such as the arc-fault current, the arc flash in the air or in the enclosure, electrode gap, and the box size. At this aim, the article proposes a simplified method to calculate the arc-fault currents, the incident energy, and arc-flash boundary, assuming as reference test the IEEE 1584 results. At first, it deals with a normalized analysis of the arc-fault currents in reference to the maximum power transfer condition. This analysis highlights the basic influence of the power factor on the fault current behavior and allows to identify an operational value of the arc resistance. In the power systems of low voltage ac ≤600 V, this article proposes a tentative criterion to evaluate the incident energy, the arc-flash boundary, and to select the adequate PPE(Personal Protective Equipment). The parameters suggested by the simplified model are identified and verified, assuming as a reference of the arc-fault current calculation with the IEEE guide. The numerical results on case studies, obtained with the proposed model, are completely consistent with the results obtained with the IEEE1584-2018 guide.

Phase-Ground Fault Current Analysis and Protection of a High-Resistance Grounded Power System

This article provides a closer look at a high resistance grounded (HRG) power system using symmetrical components. It addresses the industry confusion, “how system charging current direction reverses during phase-ground fault condition without reversal of system voltage that causes fault current flow.” It presents fault current phasor diagram that caused industry confusion which lead IEEE Std P3003.1 published without the phasor diagram with the consensus of working group members including the author of this article. In this article, the theory of symmetrical components has been used for analysis of phase-ground fault to illustrate ground fault current flow directions and its phasor diagram. The industry concept, “phase-ground fault current flows from the faulted location to ground before it returns to the power source” has been used in the analysis. This concept has not been used in the IEEE Std. 142 -2007, causing ground fault protection confusion for HRG power systems. The fault current flow direction clarification will help in the application of a sensitive voltage polarized ground fault protection relay for HRG. During phase-ground faults with very low arcing fault currents which pose a sensitivity issue on ground fault protection relays, some relevant technical papers providing techniques of fault detection are referenced in this article. Clarification on the limitation of HRG grounding contained in IEEE Std. 142-2007 for phase-ground fault current not to exceed 10 A and power system voltage not to exceed 4.16 kV (for delayed clearing of first phase-ground fault) is also included in this article.

Logistic Regression Based Arc Fault Detection in Photovoltaic Systems Under Different Conditions

This paper investigates direct current (DC) arc fault detection in photovoltaic system. In order to avoid the risk of fire ignition caused by the arc fault in the photovoltaic power supply, it is urgent to detect the DC arc fault in the photovoltaic system. Once an arc fault is detected, the power supply should be cut off immediately. A lot of field experiments are carried out to obtain the data of arc fault current of the photovoltaic system under different current conditions. Cable length, arc gap, and the effects of different sensors are tested. These three conditions are the most significant features of this paper. Four characteristic variables from both the time domain and the frequency domain are extracted to identify the arc fault. Then the logistic regression method in the field of artificial intelligence and machine learning is originally used to analyze the experimental results of arc fault in the photovoltaic system. The function between the probability of the arc fault and the change of the characteristic variables is obtained. After validating 80 groups of experimental data under different conditions, the accuracy rate of the arc fault detection by this algorithm is proved to reach 100%.

A fast arc fault detection method for AC solid state power controllers in MEA

Arc fault detection is desperately required in Solid State Power Controllers (SSPC) in addition to their fundamental functions because arcs will provoke growing harm and threat to aircraft safety. Experimental study has been done to obtain the faulted current data. In order to improve the detection speed and accuracy, two fast arc fault detection methods have been proposed in this paper with the analysis of only half cycle data. Both Fast Fourier Transform (FFT) and Wavelet Packets Decomposition (WPD) have been adopted to distinguish arc fault currents from normal operation currents. Analysis results show that Alternating Current (AC) arcs can be effectively and accurately detected with the proposed half cycle data based methods. Moreover, experimental verification results have also been provided.

A Graphical Approach to Incident Energy Analysis

The goal of an incident energy analysis is to determine the largest incident energy that a worker could be exposed to at a piece of electrical equipment. This is most commonly done using the IEEE 1584 method. It is a common observation when performing this analysis that minor variations in fault current can result in large changes in a protective device's operating time and the resulting incident energy. This would not be a problem if it was possible to remove all errors from the bolted fault calculation and the arcing fault calculation. Unfortunately, the arcing fault current calculation has some margin of error and the data used in arc flash models are often estimated. A graphical approach to determining the incident energy circumvents these problems and ensures that the worst-case incident energy is determined. This graphical approach is derived from graphs of incident energy based on protective device time–current curves. An examination of the resultant graphs reveals a few maximums in the incident energy curve. These maximums are caused by the protective devices curve, the minimum and maximum arcing fault currents, and any time limitations that are applied. As a result, the locations of these maximums are easily predicted allowing the maximum incident energy to be determined by performing the IEEE 1584 calculation at a few key current values.

Research on Arc Fault Characteristics and Detection Method

According to the arc fault mechanism of production and refer to UL1699 standard,arc fault testing system is set up,and the current waveform of arc fault and electrical equipment are collected. By analyzing time-frequency characteristics of arc fault current,paper indicates the boundedness of traditional arc fault detection method and present a brand new arc fault detection method based on fractal theory.The effectiveness and accuracy of this method is tested and verified with simulation.

Causes of residential lightning fires: Electrical arcs are at the root

This article presents evidence that a major cause of residential lightning fires is electrical arc-fault current. Such arc-fault currents are a common result of both direct and indirect lightning strikes. These faults result from lightning overvoltage damage to the insulation of electricity supply conductors and appliances. Many of these overvoltages appear to be caused by indirect lightning strikes, and a small fraction of these events also result in damage to fuel gas systems, especially thin, metallic, flexible gas lines. Fuel gas leaks resulting from this electrical damage may contribute to the fire hazard. The absence of any lightning protection on residences with exposed metallic roof penetrations is considered a major factor.

Arc Fault Recognition Method Based on Phase Space Reconstruction and Fractal Theory

A method of recognize arc fault based on phase space reconstruction and fractal theory is presented in this paper.In order to obtain the current wave under the conditions of different arc faults, the experiment platform is built according to UL1699 standard so as to sample the current wave of arc fault by the digital oscilloscope. Meanwhile the current wave of some electrical equipment with the normal operation are also sampled. The phase space track chart are obtained by the method of phase space reconstruction theory, and the algorithm about extracting characteristic quantity of arc fault current is presented based on the fractal theory. By simulating using MATLAB software, the box-count dimension of the current phase space track charts for arc fault and the some electrical equipment with normal operation are calculated, its result prove this algorithm effective and feasible.

Arcing Faults in Electrical Equipment

Electrical incidents that result in significant injuries to people are often the result of substantially unconstrained free-burning arcing-fault currents within electrical equipment. It is necessary to understand the nature of these arcs and be able to quantify the parameters before it is possible to really comprehend what is actually happening inside arcing faults and how they cause injuries to personnel in the immediate vicinity. This requires an understanding of the energy dissipation and the energy transfers in the vicinity of these uncontrolled arcs. This paper sets out to describe the physics of arcing faults and uses this to describe the energy transfers within an arcing fault. This provides a basis for describing the potential energy transfers to personnel in the vicinity of an arcing fault. This includes arc-root movements on humans and the transfer of the arc out of the body, which occurs in milliseconds. This has a significant impact on ventricular fibrillation and personal protective equipment for high-voltage workers.

아크고장 검출기술의 개발

2007년도에 9,128건의 화재가 전기적인 원인에 의해서 발생되었고, 이들 화재에 의해 사망 29명과 부상 262명의 인명피해가 있었다. 아크고장은 전기화재의 주요 원인의 하나로, 일반적으로 높은 열을 발생시키며 쉽게 주변의 인화성물질을 점화시킨다. 그러나 기존의 차단기는 과전류, 단락전류, 누설전류에 대해서만 동작하기 때문에, 이에 대해서는 현재 특별한 보호책이 없는 실정이다. 본 논문은 직렬아크 고장전류에 의한 전선의 발화특성에 대한 실험에서 얻어진 결과를 통해 UL에서 제안하고 있는 기준이 국내의 현실에 적절하지 않음을 제시하였고, 이 결과를 기초로 개발된 기술의 동작특성 실험을 실시하여 아크고장회로를 보호할 수 있는지에 대한 신뢰성을 확인하였다. 모의실험을 통한 동작특성 분석결과, 개발된 아크고장 검출 기술을 적용하면 전기화재의 주요원인인 아크고장에 의한 화재를 현저히 저감시킬 수 있을 것으로 판단된다. In 2007, 9,128 fires were actually caused by electrical faults and these fires resulted in 29 deaths and 262 injuries. Arc-faults were one of the major causes of these fires. When an unintended arc-fault occurs, it generates intense heat that can easily ignite surrounding combustibles. But, because conventional circuit breakers only respond to overloads, short circuits, and leakage currents, the breakers do not protect against arcing conditions. This paper presents results obtained in experiments on ignition behavior of wire by series arc fault currents and techniques developed to detect the arc-faults. The developed technique was tested after installation to make sure that they are working properly and protecting the circuit. If the developed arc fault detection technique is applied, the electrical fires caused by an arc-fault can be reduced.

Design of an Arc Current Controller for Arc Interruption

In this paper, an arc current controller was designed for the interruption of arc fault currents occurred in a low voltage network. Arc in an electrical network represents the characteristics of low current, high impedance, and high frequency. Conventional controllers do not have arc current interrupt functions. Thus, an arc current controller was designed for the interruption of arc fault currents.

Detection of High Impedance Faults Using the Randomness of Even Harmonic Currents

In this paper, we propose a new method for the detection of high impedance faults, which use the randomness of even order harmonic currents. From the analysis of the staged fault test data, it was found that there exists an intermittent arcing phenomenon in most high impedance fault and the waveform of this arcing fault current has an unsymmetric shape in each cycle. From these facts, we present new criterions for fault detection, all of which are based on changes of even order harmonic powers in fault currents. The proposed detection method under these criterions is compared with existing detection methods for high impedance faults through the analysis of a staged fault data and a normal switching event data. By this comparison, it will be shown that the detection method presented in this paper is superior to existing methods and that high impedance faults can be easily distinguished from normal switching events. Microprocessor based protective relays, which detect high impedance faults by using the proposed methods, have been constructed and installed on KEPCO substations and tested during last two years.

Harmonic behavior during arcing faults on power distribution feeders

The waveforms of normal and arcing fault currents on power distribution feeders are investigated and compared in terms of the percentage amplitude with respect to the amplitude of the normal fundamental. The purpose of the study is to find better parameters to indicate arcing faults. The effect of capacitor banks on distribution feeder harmonics is discussed briefly.

Studies of Power Arc Faulta in SF6 Insulated Equipment

Power arc behaviour in gas insulated equipment and the influence of arc motion on damage resulting from simulated faults were investigated in the laboratory. Experiments were carried out with power-frequency currents up to 22 kA in a co-axial test chamber insulated with pressurized SF6 and air. Arc motion was measured with time-of-flight and infrared thermal imagery techniques for various fault currents, geometries and pressures. A linear, relationship between the axial arc velocity and fault current was established. For a typical 138 kV SF6 bus duct, this velocity is 100 cm/s·kA. The influence of spacers on the motion of arcs in the gas insulated equipment was studied with respect to temperature rise of and damage to the sheath

Research and Implementation of Low Cost Arc Fault Circuit Interrupter

With the increasing of residential electricity and electrical fire accidents increasingly serious also, fault arc as one of the important causes of electric fire accident has aroused extensive attentions. The conventional breakers or protection device are unable to provide comprehensive protection of arc fault. And now a special apparatus named AFCI (Arc Fault Circuit Interrupter) has been proposed. But the performance of the AFCI needs improvement, so the study of arc fault characteristic to propose arc fault diagnosis method has important significance. In the paper, an arc fault experiment platform is set up so as to acquire the arc fault data. Then FFT is applied to analysis the frequency characteristics of the arc fault current. Result proved that the appearance of arc fault lead to the increase of the harmonic order. An arc fault detection technique based on the grid fractal theory is proposed in the paper. By analysis the change rate of circuit current, the arc fault can be diagnosis. As the arc fault is difficult to diagnosis, the cost of the conventional arc fault circuit breaker developed before is very high. While in the paper, a low cost AFCI based on the technique for low voltage distribution system is introduced. The hardware and the software of the AFCI are present in the paper. After test, the results show that the device has a good performance in arc fault protection. And it is suitable for electrical fire protection

The Problem of Arcing Faults in Low-Voltage Power Distribution Systems

Many cases of electrical equipment burndown arising from low-level arcing-fault currents have occurred in recent years in low-voltage power distribution systems. Burndown, which is the severe damage or complete destruction of conductors, insulation systems and metallic enclosures, is caused by the concentrated release of energy in the fault arc. Both grounded and ungrounded electrical distribution systems have experienced burndowns, and the reported incidents have involved both industrial and commercial building distribution equipment, without regard to manufacturer, geographical location, or operating environment.