Characteristics of the Arc Voltage of a High‐Current Air Arc in a Sealed Chamber

The effect of the arc voltage on various factors of design and control was investigated for high currents in order to develop design guidelines for circuit breakers. In this study, the dependence on such factors, namely, the current, arc length, electrode surface area, and internal pressure of the arc voltage, was evaluated quantitatively. As a result of the evaluations, it was estimated that the arc voltage near the electrode surface rises linearly with the arc current and the power ?0.8 of the surface area, and that the voltage in the arc column rises as the 0.3 power of the pressure increase. We confirmed the validity of the estimated voltage characteristics by comparison with the generated voltage in an actual arc‐extinction chamber. The characteristics of the estimated voltage can provide effective guidelines for the design of arc extinguishing chambers. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 186(1): 34–42, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22487     

Measurement of arc properties and spectrum intensity in AC arcs surrounded by plastics

This paper describes experimental results on the arc‐quenching properties under the condition of being surrounded by plastic found in low‐voltage circuit breakers. The alternating current used is from 500 to 1100 A(rms) with 60‐Hz frequency. The plastic materials investigated here are polymethylpentene (? C₃H₅? ), polymethylmethacryl‐ate (? C₅H₈O₂? ), polybutyleneterephthalate (? C₁₂H₁₄O₄? ), polycarbonate (? C₁₆H₁₈O₃? ), and PTFE (? C₂F₄? ). In conjunction with the usual arc current and voltage measurements, two images of spectrum intensity of 511 and 522 nm emitted from copper electrode vapor are detected simultaneously by using two bandpass filters. A high‐speed digital video technique (4500 frames per second) is used for analyzing the transient space movement of copper vapor. The arc voltage is strongly influenced by the plastic materials rather than the arc current. Especially in the case of ? C₃H₅? , the magnitude of the arc current was strongly limited by its high arc voltage. On the other hand, in the case of ? C₂F₄? , the arc cannot be interrupted and the arc voltage is the lowest value of all. The arcing period is also much influenced by the type of plastic material (the shortest and longest were ? C₃H₅? and ? C₂F₄? , respectively), while it shows almost no change with amplitude of arc current. The spectroscopic images of copper vapor obtained by high‐speed video for transparent plastics of ? C₅H₈O₂? and ? C₁₆H₁₈O₃? showed that the vapor expanding speed of the former is considerably faster than that of the latter. The results indicate strongly that the arc‐quenching property is affected by the ablation and blast speed of arc‐surrounding plastic materials. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(1): 38–47, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10002     

特高压半波长输电线路潜供电弧低压模拟实验研究

潜供电弧是半波长输电技术面临的关键问题之一,因此针对特高压半波长输电线路潜供电弧进行了低压物理模拟实验研究。通过分析半波长线路潜供电流与恢复电压特性,进行回路等效变换,获得满足等价性的低压模拟实验回路拓扑,通过实验获得了不同潜供电流值、恢复电压梯度等组合方案下潜供电弧的燃弧时间,并与常规输电线路的情况进行对比。比较了短路电弧与潜供电弧的电流、电压特征,并通过高速摄像仪获得潜供电弧的运动轨迹,分析了风速等因素对短路电弧与潜供电弧运动的影响机制。研究表明:当潜供电流值<150A,恢复电压梯度<3.9kV/m时,潜供电弧将快速自灭;当潜供电流值>240A,恢复电压梯度>7.0kV/m时,潜供电弧将会长时间燃弧;风力是影响潜供电弧运动与燃弧的关键因素。研究结果可为解决半波长输电技术的潜供电弧问题提供参考依据,同时对常规线路潜供电弧以及长间隙电弧研究具有借鉴价值。     

Effects of multiple interruptions on post‐arc current,reignition, and lifetime of distribution breaker

The purpose of this investigation is to study the interruption performance of the Molded Case Circuit Breaker (MCCB) currently used for the protection of low‐voltage circuits. It is anticipated that interruptions, especially numerous high‐current interruptions, will degrade interruption performance. In order to investigate the performance change after many interruptions, it is important to understand the interruption characteristics. Multiple‐interruption experiments at large currents were conducted and the phenomena which govern the success or failure of interruption were identified. It was shown that after multiple interruptions a post‐arc current begins to flow and that the duration of the arc is ten to a few hundred microseconds. In order to explore the relationship between the post‐arc current and the degradation of the interruption characteristics, the conditions governing the post‐arc current were investigated experimentally. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(4): 42–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10358     

EMTP simulation of SLF interrupting performance for two serially connected arcs with different arc parameters

This paper shows the calculation of SLF interrupting performance for two serially connected Mayr‐type arc models with different arc parameters by using EMTP‐ATP Models. Arc model 1, assuming an air circuit breaker, has large arc time constant and large arc power loss. Arc model 2, assuming a vacuum circuit breaker, has small arc time constant and small arc power loss. It was not possible for arc model 1 to interrupt 300 kV‐63 kA‐90% SLF by itself. However, by connecting these arc models in series, interruption became successful, even if arc model 2 was reignited at low voltage a few microseconds after current zero. These computations suggested that serial connection of the two circuit breakers with different breaking characteristics would give a totally excellent circuit breaker by making the best use of advantages of each circuit breaker. EMTP‐ATP Models were very useful in solving the arc models, which are expressed by differential equations and coupled with the electric circuit. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 25–33, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10020     

Insulation recovery characteristics of 500 kV class dc insulator assemblies after arc extinction

The insulation recovery characteristics of 500‐kV‐class dc insulator assemblies were measured. Switching impulse voltage was applied to a tension insulator assembly and three kinds of suspension insulator assemblies (V‐, Y‐, and I‐arranged) following arc extinction. Arc current ranged from 400 A to 4000 A and arc duration from 0.1 s to 0.4 s.

• (1) All insulator assemblies show slow insulation recovery after arc extinction up to an impulse withstand voltage of 100 to 200 kV. The insulation recovery rates increase near the impulse withstand voltage of 500 kV.
• (2) At arc current of 400 to 4000 A, for a duration of 0.1 s, the recovery rate for all insulator assemblies decreases with increases in arc current. This is believed to be due to the increases in the postarc gas temperature caused by the increased arc current.
• (3) When the arc duration is increased from 0.1 s to 0.2 s at a current of 4000 A, the insulation recovery of the V‐ and Y‐arranged assemblies is delayed by 0.05 s. This is believed to be due to the increases in the temperature of postarc gas caused by the longer arc duration.
• (4) By measuring the insulation recovery characteristics of the tension insulator assembly and three kinds of suspension insulator assemblies with an arc current of 4000 A and an arc duration of 0.1 s, the minimum value of nonvoltage time for a 500‐kV dc transmission line is calculated to be 0.17 s. © 1999 Scripta Technica, Electr Eng Jpn, 129(3): 29–39, 1999

     

Relationship between current waveform just before current zero and interruption ability of high‐speed VCB

A high‐speed vacuum circuit breaker which forces the fault current to zero was investigated. The test circuit breaker consisted of a vacuum interrupter and a high‐frequency current source. A vacuum interrupter with an axial magnetic field electrode and a disk‐shaped electrode was tested. The arcing period of the high‐speed vacuum circuit breaker is much shorter than that of a conventional circuit breaker. The arc behavior of the test electrodes immediately after the contact separation was observed by a high‐speed video recorder. The relation between the current waveform just before the current zero point and the interruption ability was investigated experimentally by varying the high‐frequency current source. The results demonstrate the interruption ability and the arc behavior of the high‐speed vacuum circuit breaker. Effective current interruption is made possible by a low current period just before the current zero point, even though the arcing time is short and the arc is concentrated. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 172(2): 20–27, 2010; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20915     

10kV配电网系统弧光接地过电压研究

比较了中性点直接接地、不接地、经消弧线圈接地等接地方式的安全性和供电特点,从理论上利用EMTP/ATP电磁暂态程序建立仿真模型,以吉林省66 kV某变电站发生的10 kV单相接地故障为例,计算了弧光接地过电压并分析了降低弧光接地过电压的措施,得出中性点经消弧线圈接地,能够降低弧光接地过电压的幅值;接地残流小于10 A时接地电弧易于自熄弧;弧光接地过电压标幺值由中性点不接地时的2.01降至0.97;在脱谐度绝对值相等条件下,消弧线圈工作在过补偿和欠补偿状态下的弧光接地过电压幅值相差不大。     

Influence of power supply on continuity of vacuum arc with Al cathode and N2 flow under medium vacuum

The continuity of a steered vacuum arc with Al cathode and N₂ flow at a pressure between 0.1 and 5 Pa is investigated. Two constant‐current power supplies (60 V open‐circuit voltage/30 V load voltage and 310 V/240 V) and a constant‐voltage power supply with open‐circuit voltage 550 V are used. The arc current is 30 A, the N₂ flow rate is 20 ml/min, and the transverse magnetic field density at the cathode edge is 1.2 mT. The following results are obtained. (1) When the power supply with lower open‐circuit and load voltages is used, a decrease in pressure causes the arc to lose sustainability. (2) When the power supply with high open‐circuit and load voltages is used, the arc can continue even at lower pressure. (3) When the power supply with higher load voltage is used, abnormal discharge behind the magnet field guide‐disk may occur at lower pressure. The above‐mentioned influence of power supply on arc continuity is interpreted in terms of column fall and generation of a new cathode spot. © 1999 Scripta Technica, Electr Eng Jpn, 128(3): 9–15, 1999     

Effect of polymer ablation gas on arc quenching properties around current zero

The influence of polymer ablation on arc properties such as the temperature distribution and arc conductance in the current decay process was investigated by numerical approaches. A numerical thermofluid model was developed for a simplified circuit breaker with POM or PTFE ablation. In this model, thermal plasma‐polymer solid coupling phenomena such as melting and evaporation were taken into account without any empirical model based on measurements, unlike other existing numerical thermofluid models. The dominant process for the decay of arc conductance was examined by changing the thermodynamic parameters such as the melting and boiling temperatures of solid polymers, or the thermal conductivity and electrical conductivity of the ablation gas. It was found that the gas density, thermal conductivity, and electrical conductivity of the ablation gas were more effective for decaying arc conductance than any other thermodynamic parameters. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(3): 32–45, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22274     

石英砂限流和熄弧的原理研究

通过在简单的电弧模型中运用功率平衡原理可以证明,在给定电流时,电弧的直径愈小,则电弧电压愈高,石英砂中的电弧,正是由于被限制在熔体汽化后遗留下的很小空腔中燃烧,故电弧电压很高,从而具有强烈的限流和熄弧作用。     

福州—温州1000kV特高压同塔双回输电线路潜供电流和恢复电压研究

应用EMTPE仿真软件,计算了福州-温州特高压同塔双回线路潜供电流和恢复电压,分析了潜供电流和恢复电压的主要影响因素.通过对福州-温州特高压线路潜供电流和恢复电压的综合分析,提出了高抗中性点小电抗取值建议.     

Generation of Anode Spot in Low‐Current DC Vacuum Arcs by the Effect of Embedded Magnet in the Anode

Experiments were conducted with the aim of keeping low‐current DC vacuum arcs stable. A permanent columnar magnet was embedded in the anode and a permanent disk‐shaped magnet was arranged behind the anode. As result, the arc plasma is strongly constricted to a column and a light emitting point appeared on the anode surface. Generation of the anode spot was confirmed by detecting anode metal vapor and ions using mass and spectroscopic analyses under low‐current arcs of less than 20 A. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

电气参数和机械参数对继电器直流电弧的影响

电气参数和机械参数是影响小型继电器直流电弧开断性能的主要因素。在实验中改变电源电压、负载条件、继电器分闸弹簧数量以及触头对数,测量继电器开断过程中直流电弧的电压电流波形,总结电弧燃弧时间和能量的规律。研究表明:电源电压升高极大地提高了电弧燃弧时间和能量;电源电压一定时,电弧的燃弧时间和能量随电流的上升而增长;电压等级较低时,继电器分断初速度对燃弧时间和电弧能量的影响不大,电压等级较高时,速度对燃弧时间和电弧能量影响较显著;双组触点分断负荷相对于单组触点的情形大大减少了电弧的燃弧时间和电弧能量,有利于减轻电弧对触头侵蚀。     

Arc behavior and interruption ability of uniform vacuum arc control technology and its application to vacuum interrupter

The vacuum arc characteristics and high current interruption ability of several different sized electrodes applied in the uniform vacuum arc control method named self arc diffusion by electrode (SADE) are presented. The arc behavior of the test electrode during the arcing period was observed by a high‐speed video camera. At extremely high interruption currents, the arc of the conventional axial magnetic field (AMF) electrode concentrates, causing local heating of the electrode. However, the arc of the SADE diffuses over the whole contact area thus avoiding local heating. The interruption ability of SADE is about twice as much as that of the conventional AMF for the same sized electrode. By applying this arc control method to vacuum circuit breaker (VCB), it can be made more compact and lighter than the conventional type. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于HCMAC神经网络的故障电弧检测方法

低压故障电弧电流的有效值往往小于热脱扣器的动作电流,导致传统的电路保护装置失效.模拟低压电气线路中的故障电弧,利用电流采样装置对故障电弧电流进行采样.在分析故障电弧电流波形特征的基础上,利用HCMAC神经网络对电流波形的各周期均值、斜率和小波变换高频系数三个判据进行综合评判,有效克服了单一判据的局限性.仿真结果表明,基于HCMAC的故障电弧检测方法可有效识别故障电弧特征,提高辨识故障电弧的准确率.     

Investigation of a new extinguishing principle for a gas circuit breaker

A self-extinguishing principle of a gas circuit breaker (GCB) without puffer action (autopuffer GCB) using an external magnetic field was investigated to improve the interrupting capability in the small current region (several kA). Properties of the rotating speed of an arc, the arc voltage, and the gas pressure rise in an expansion space under the external magnetic field were studied experimentally. The relation between the interrupting capability and the radial magnetic flux density in the autopuffer GCB with a permanent magnet (magnet-assisted autopuffer GCB) was obtained experimentally and also analyzed numerically. The results are summarized as follows.

• 1 The arc column is driven in the azimuthal direction by the radial component of the external magnetic field.
• 2 The rotating speed of the arc driven by the radial magnetic field of a permanent magnet remains constant in the arc current range below several kA, and it decreases with an increasing current in the current above several kA.
• 3 Since the arc rotation raises the arc voltage and gas pressure in the expansion space, the gas flow from the expansion space to the arc increases in the vicinity of current zero. The interrupting capability is then improved in the small current region.
• 4 It is confirmed that the magnet-assisted auto-puffer GCB has a good interrupting capability not only for the large current region but also for the small current region.

     

快速接地开关熄灭同杆双回输电线路潜供电弧的研究

由于同杆双回线间较强的耦合作用,造成潜供电弧不易自熄,影响了单相自动重合闸的成功率,必须采取措施熄灭潜供电弧.在分析了各种熄弧措施的特点后,提出采用快速接地开关(HSGS)熄灭同杆双回线的潜供电弧.利用相模变换的方法和EMTP计算了采用HSGS后线路的潜供电流和恢复电压,结果表明HSGS用于同杆双回输电线路可显著减小故障相上的恢复电压和潜供电流,使潜供电弧可靠熄灭.     

Fault-locating method using harmonic components of the arc-voltage waveform

This paper describes a new type of the fault-locating method by using voltage and current values measured in a substation or transmission lines. This method is based on the impedance method and consists of the following items: (1) analysis of harmonic components in voltage waveforms measured in the substation; (2) estimation of the arc fault voltage on the lines; (3) calculation of the line impedance voltage drop; and (4) determination of the fault-locating distance. The availability of this method was confirmed by arc fault tests on 6-kV cable and overhead distribution lines. As a result, the fault-locating error of this method was proved to be roughly less than 10 percent.     

Development of SF6 Gas‐Insulated Disconnecting Switch with Spiral Electrodes Using Motor Operating Mechanism

Gas‐insulated switchgear (GIS) requires reliability and economic efficiency. Circuit breakers, disconnecting switches (DS), and earthing switches have been designed to be more compact. DS requires performance in terms of insulation and current interruption. The bus‐transfer current is the highest among all current interruption requirements for the DS. To develop an alternating current DS driven at a lower speed, it is necessary to reduce the electrode damage. This paper describes the fundamental characteristics of current interruption in a magnetically driven arc using a spiral electrode. Since the arc is rotated by magnetically driven force, the arcing time in the spiral electrode is shortened to about one‐third compared with that of a plain breaker electrode. The DS using a magnetically driven arc was confirmed to comply with the bus‐transfer current switching requirements in the JEC standard. Moreover, a physical model of the magnetic driven arc was constructed, and the behavior of the arc was evaluated quantitatively. As a result, performance of current interruption could be predicted. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(3): 31–39, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21147