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.     

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     

Comparing direct and synthetic tests for interruption ofline-charging capacitive current

Using a validated arc model, this paper analyzes current distortion and voltage waveforms during both direct and synthetic tests for interruption of line-charging capacitive current by power circuit breakers. Although the voltage of the electric arc drawn between breaker contacts may produce significant current distortion, it is demonstrated that the most significant parameter affecting the breaking capacity of power circuit breakers in capacitive-current switching tests is the voltage jump appearing across breaker contacts immediately after current interruption. It is essential to correctly define the supply circuit impedances and the associated voltage jump so as not to reduce or increase this test severity unduly     

A new interruption method for low-voltage, high-capacity, air-breakcontactors through suppression of hot blowoff gases

The purposes of this study are to suppress the blowoff of hot gases from an arc chamber and to shorten the arcing time in the interruption of overcurrents. The blowoff of hot gases is suppressed by the cooling action of a porous metal plate attached in front of the gas exhaust holes of an arc chamber. From heat analysis, it is estimated that exhaust gas temperature is reduced to less than 10% of the temperature of hot gases in the arc chamber using the porous metal plate. The arcing time is shortened by a unique commutation electrode and arc runner. For interruptions of a 6 kA current in a 480 V circuit, the maximum arcing time of the new method is shortened by about 40% compared with that of a conventional method. From observation using a high-speed framing camera, it is concluded that the shortening of arcing time is due to an effective arc-drive by the commutation electrode and arc runner. The new method has been applied to contactors of 600 A and 800 A frames having the maximum rated operational voltage of 660 V     

交流电弧沿染污绝缘表面发展过程的研究

作者用高速摄影机拍摄了交流电弧沿染污绝缘表面发展的全过程,同时记录闪络过程中外施电压和泄漏电流的变化。通过综合分析,阐述了交流污闪电弧的物理特征,电弧的极性效应、电弧延伸的最大速度以及临界闪络电压、电弧长度,为研究污秽闪络机理提供了科学的依据。     

低压断路器电弧转移现象的光学诊断

大多数微型低压断路器是靠把电弧从起始位置移到灭弧位置以分析短路电流的。本文３借助成像及光谱技术着重研究电在离开弧触头区时发生的现象。采用了一种新的多镜头电子照相机，它的爆光时间可达１００ｎｓ，可在一行内拍摄几幅电弧照片。由于使用了干涉滤光片，可以将铜，氢及碳分子这些典型粒子的空间辐射分布显示出来。     

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     

高湿热环境下智能电能表计量误差特性分析

针对现场复杂环境对智能电能表运行特性作用机理不清晰的问题,借助高湿热环境长时间现场运行试验,研究智能电能表计量误差随日历时间变化规律,重点分析电流、温度、相对湿度、风速、光照、气压对电能表计量误差的影响,借助计量误差均值与标准差阐释电气和环境因素对智能电能表运行特性的影响规律,获得计量误差演变规律模型。通过量化电气和环境因素对电能表计量误差的影响,发现负载电流是影响智能电能表计量特性的最重要因素,温度和湿度是影响智能电能表计量特性的次重要因素,风速对电能表计量特性的影响最弱。研究结果对提高智能电能表可靠性和稳定性具有参考价值。     

35kV架空输电线路间隙灭弧的研究

为解决35 kV架空输电线路的雷击问题,研制了在35 kV架空输电线路上的防雷保护间隙喷射气流灭弧装置。该装置运用了"瞬时疏导"的防雷理念,能够在线路发生雷击闪络时有效地保护绝缘子串免受工频电弧的灼烧,在疏导雷电能量后能够迅速切断工频续流电弧,实现既可以限制绝缘子的外部过电压又可以避免断路器频繁跳闸的功能。笔者在链式电弧模型的基础上结合激波理论研究喷射气流条件下电弧的运动,对电弧的熄灭过程进行了讨论。在高压试验中借助高速摄像机和数字示波器,获取了在高速气流作用下电弧被迅速熄灭的过程图像和数据。     

SF_6断路器开断能力数值预测方法研究综述

综述了SF6断路器极限开断能力以及介质开断能力的数值预测方法的最新研究进展。电流过零前200 ns的电弧电导(G200)是判断断路器热开断能力的一个重要参数,为计算G200,对电弧特性进行模拟,在燃弧阶段采用磁流体动力学模型,而在接近电流零区采用Mayr模型,从而建立相应的电路模型来确定电弧时间常数和电弧功率损耗系数等参数,以分析高压断路器的热开断能力。为判断电击穿能力,需要根据电弧过零时灭弧室内的每一点的压力和温度值,确定对应点的临界击穿场强分布Ec,同时计算在暂态恢复电压作用下灭弧室内的电场分布Ea,然后通过比较灭弧室内各处Ea和Ec的值,就可以判断出灭弧室内不同区域电击穿几率的大小。     

Study of DC circuit breaker of H2‐N2 gas mixture for high voltage

Global warming caused by such gases as CO₂ is a subject of great concern. Automobile emissions are an especially great problem in this respect. Therefore, hybrid cars are being widely developed and used. Because hybrid cars use electric power and gasoline, their emissions of CO₂ are reduced. The electric motor of a hybrid car is driven by a battery, which has large capacity. Therefore, relays must interrupt a high DC current on switching between the electric motor and the gasoline engine, and hydrogen gas‐filled relays are used for the purpose. In interruption tests in which we investigated the basic characteristics of hydrogen gas, the DC current did not reach a current‐zero point. Thus, the current must be coerced to zero by using a high arc voltage. The loss coefficient and arc voltages of hydrogen are high, and we therefore performed interruption tests using a high arc voltage. Interruption tests and dielectric breakdowns test of air, pure hydrogen, and a hydrogen‐nitrogen mixture indicated that an 80%–20% H₂–N₂ mixture is the most effective. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(2): 9–17, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21042     

高温高速气流温度测量方法的研究

本文提及的测量方法是针对高温高速气流在温度测量过程中存在着气流温度本身在变化与温度传感器有一定响应时间这2个难点而设计.它是通过启动弹射装置,把热电偶测量端射入气流中,经过一规定时间后,将其自动收回,测出热电偶测量端的瞬时温度,进而就可推算出被测气流的真实温度值.通过此方法测量后,可确定热电偶的时间常数,而当测量时间大于3倍热电偶的时间常数时,动态响应误差可以减到最小.另外,热电偶的测量端体积要尽可能小,这样不仅能提高响应时间,把动态响应误差可以减少到最小,而且还能克服滞后带来的影响.     

Optical measurement of non-uniform electric field vectordistribution in a dielectric liquid using triplet measurementsystem

We have carried out measurements of three-dimensional nonuniform electric field distribution using Kerr electrooptic measurement with a reconstruction technique. A conventional measurement system was composed of He-Ne laser, a polarizer, a quarter-wave plate, an experimental cell, an analyzer, and a photo-detector. For the measurement of an electric field vector distribution, it was necessary to measure light intensity with changing the optical axis of optical wedges, i.e., the polarizer, the quarter-wave plate and the analyzer. Moreover, the intensity measurement must be carried out at many points from &thetas; = 0 to π around the electrode system. Therefore it took considerable time to measure the electric field distribution. We have improved the measurement system by a cell with six optical windows and three optical systems. Using the improved measuring system, it was possible to measure the non-uniform electric field vector distribution faster     

基于锁定放大器的光学电流互感器的研究及应用

随着电力系统的发展,传统的直流互感器因为种种缺点已经难以适应超高压直流测量的需要.光学电流互感器自问世以来,以其无饱和、高绝缘、抗电磁干扰等诸多优点成为传统电磁式电流互感器的替代产品.但长期以来因种种不利因素的困扰OCT的实用化迟迟没有提上日程.本文针对提高光学电流互感器的输出信噪比展开研究,分析OCT的信噪特性,进行...     

一种新的基于霍尔传感器的电流测量方法

提出了一种新的电力电流测量方法。该方法采用了无集磁铁芯的霍尔传感器,将4个霍尔传感器对称地分布在通流母线的周围,传感器的输出联结到权值加法器上。权值加法器实现了一种均值操作效应,因此加法器实际的输出是4个霍尔传感器输出的平均,该方法降低了外部的磁场干扰。利用传统的电流互感器和按照新方法设计的霍尔电流互感器进行了实验对比,结果表明霍尔电流互感器虽然还不能和达到传统的高精度CT,但是仍能达到0.5~1的精度等级,说明了该方法的可行性。     

采用工频通信技术的低压用户相线识别装置

采用“拉闸验电”的方法确定用户的变压器台区和相线属性存在很多弊端。在不中断对用户供电的情况下．直接对电网任意点进行丁线检测．经采集数据和自动分析．作出被检测点相线属性的识别,可为配电网管理提供必要的基础数据．对电力工频通信的信息通道与相线识别装置的技术实现进行了重点讨论．该装置能方便快捷地识别出用户或用电设备在电网中的电气属性．具有较高的经济效益和社会效益。     

光电传输系统在电力系统测量中的应用

相对于传统的采用电缆传输测量信号的方式,采用光电传输系统传输测量信号具有良好的绝缘性能和抗电磁干扰特性,因而其在电力系统测量领域具有广阔的应用前景。光电传输系统一般由发射电路、光纤和接收电路三部分组成,根据信号调制和解调方式的不同,在电力系统测量中可将光电传输系统分为调幅方式、压频(V/F)转换方式和模数(A/D)转换方式三种。本文在介绍光电传输系统组成及结构的基础上综述了这三种方式的光电传输系统在电力系统电压、电流、电场强度、泄漏电流以及雷电流等测量中的应用,并分析了光电传输系统应用于电力系统测量中需进一步解决的一些问题。相信随着技术的进步以及电力自动化的发展,光电传输系统在电力系统测量中必将得到越来越广泛的应用。     

远程视频监控系统中电源的检测

提出了一种结合多种监控方式的远程视频监控系统并着重介绍了其电源检测模块。该模块以电能质量管理芯片DS2438为核心实现对太阳能蓄电池电压、电流、温度的直接测量,并结合实验测得的电压-电量对应曲线实现对剩余电量的间接估计,实测证明该模块的测量误差在允许范围内,可以较为精确地反映蓄电池的状态,提高远程监控系统运行的可靠性。该系统可应用于野外环境下电力输电线路的安全保障环节,保障电力系统的安全运行。     

气吹作用对CO2、CO2/C4-PFN、CO2/C5-PFK混合气体燃弧特性的影响

CO2及其混合气体在替代SF6方面已表现出较大的应用潜力,研究其燃弧特性对于新型断路器的研发具有重要意义。为此设计了模拟直动式和压气式高压负荷开关的燃弧过程的实验装置,搭建了多参量综合测量的实验平台,针对CO2及其与C4–PFN、C5–PFK混合气体在拉弧以及喷口限制吹弧条件下的燃弧特性开展了实验研究,对燃弧过程中的电弧电压、电弧电流以及电流过零附近的零区特性进行了测量,并利用Mayr电弧模型,对比了不同燃弧实验中CO2及其与C4–PFN、C5–PFK混合气体的弧后击穿特性。研究发现:气吹作用对于小电流期间电弧的能量耗散有着极强的促进作用;在拉弧实验中,CO2气体的热开断性能大约为SF6的50%,C5–PFK–CO2混合气体的热开断性能约为SF6的75%,而C4–PFN–CO2混合气体则与SF6的热开断性能相当;在吹弧实验中,CO2、C5–PFK–CO2和C4–PFN–CO2混合气体的热开断能力分别大约为SF6的45%、68%和91%。     

直流偏磁下电流互感器测量特性分析

电流互感器作为电力系统的基本测量单元,其性能对电能计量的准确性有重要影响.随着非线性负荷和绿色能源的大量接入,供电线路电流中出现的直流分量可能严重影响电流互感器的测量准确性,甚至会造成电流互感器铁芯饱和.因此,十分必要对直流偏磁下电流互感器的测量准确性进行评估.文章基于对电流互感器电磁物理特性的分析,建立了存在直流偏磁下表征电流互感器测量特性的解析模型,推导出了电流互感器测量准确性与安匝数、铁芯尺寸、铁芯材料、二次负荷等参数之间的关系式,并对所建模型进行仿真验证得到的结果,对直流偏磁下电流互感器的测量特性进行了讨论.