电气设备空气中放电的分解气体分析法检测技术研究现状及展望

分解气体分析法通过检测故障产生的气体组分诊断设备故障,是检测电力设备故障的重要方法,某些应用场合具有不可替代的作用。然而目前该方法只在绝缘油、SF_6等绝缘介质的场合有应用,对于空气这一最重要的绝缘介质还没有应用。文中在简述空气放电衍生物气体产生理论的基础上,分析了采用分解气体分析法检测空气中放电的可行性,并对相关分解气体分析法的应用及研究现状、空气分解气体产生规律等进行了综述。最后提出需要进一步研究问题包括空气气体分解演化规律及影响因素、气体特征与放电的关系、放电识别方法等。     

高湿条件下空气间隙放电规律的试验研究

湿度是影响电力系统外绝缘的一个重要因素,但国内外相关研究较少涉及到湿度较高的情况。笔者在人工气候室开展球间隙放电试验,研究湿度(尤其是高湿条件下)与间隙放电电压的关系。研究结果表明,在湿度较低(80%以下)条件下,空气间隙放电电压随相对湿度的增加而增加;而在湿度较高(80%以上)条件下,有无凝露对放电电压的影响较大,无凝露时随着相对湿度的增加放电电压略有下降,但在湿度较高且球表面出现凝露时,间隙放电电压严重降低,甚至降低到一半。笔者利用ANSYS计算了球表面有无凝露时的球间隙电场分布,结果表明,凝露畸变了原有球间隙电场,使得最大场强增大到原电场的两倍,造成间隙放电电压严重降低,与气候实验室的结论一致。     

高湿条件下空气间隙放电规律的试验研究

湿度是影响电力系统外绝缘的一个重要因素,但国内外相关研究较少涉及到湿度较高的情况。笔者在人工气候室开展球间隙放电试验,研究湿度(尤其是高湿条件下)与间隙放电电压的关系。研究结果表明,在湿度较低(80%以下)条件下,空气间隙放电电压随相对湿度的增加而增加;而在湿度较高(80%以上)条件下,有无凝露对放电电压的影响较大,无凝露时随着相对湿度的增加放电电压略有下降,但在湿度较高且球表面出现凝露时,间隙放电电压严重降低,甚至降低到一半。笔者利用ANSYS计算了球表面有无凝露时的球间隙电场分布,结果表明,凝露畸变了原有球间隙电场,使得最大场强增大到原电场的两倍,造成间隙放电电压严重降低,与气候实验室的结论一致。     

空气湿度对开关柜局部放电影响的试验研究

介绍暂态对地电压法检测10 kV开关柜局部放电的基本原理,结合具体试验,就空气湿度对10 kV开关柜局部放电的影响进行研究.根据不同湿度条件下局部放电产生的暂态对地电压信号幅值,结合经验判据对10 kV开关柜内部绝缘子的绝缘状态进行评估.     

压力空气绝缘起始局部放电电压特性的模拟实验研究

空气绝缘起始放电电压在不同压力下表现出不同的特征。介绍了在不同电极系统和不同压力下的空气绝缘局部放电模拟实验方法,对气体放电机理、电子崩产生过程以及空气压力对放电起始电压的影响进行分析探讨。通过模拟实验得出,在给定电极间隙下气体的起始放电电压随气体压力的增大而增大。     

220kV组合电器超声波局部放电故障检测及处理

针对某220kV变电站组合电器气室内部异响,开展诊断性带电检测工作,通过超声波局部放电检测、组合电器设备SF_6气体湿度及分解物检测,确定了故障原因并进行了处理。     

湿度、气压对气体放电参数影响的实验研究

在不同气压下,改变空气绝对湿度,用稳态汤逊实验法(SST)测量了空气电子电离系数α和附着系数η,分析了空气绝缘强度受绝对湿度变化的影响和α、η与气压,绝对湿度的变化关系。提出修正气体放电电压时应考虑湿度、气压的综合作用。     

SF6电力设备局部放电与分解气体组分关系的研究进展

介绍了SF6放电分解气体的基本原理,对目前几种检测SF6分解气体的方法进行对比分析,综述了不同缺陷条件下局部放电与SF6分解气体组分的关系。     

GIS中局部放电与气体分解产物关系的试验

SF6分解气体检测法,因其不受电磁噪声和振动干扰,同时也适用于过热故障的检测等优点,成为对GIS设备进行局部放电检测诊断的重要手段,应用前景广阔。为填补现有文献中关于GIS设备局部放电与SF6分解产物关系的研究空白,在实验室建立了一套能够检测SF6分解气体产物的GIS局部放电研究平台,利用长期加压法研究了局部放电类型、放电严重程度以及气体压强对SF6气体分解产物体积分数的影响以及分解产物体积分数随时间的变化趋势。研究结果表明:在尖刺放电、悬浮放电、沿面放电3种类型中,GIS设备中均产生SOF2+SO2气体与HF气体,上述两种分解气体可作为检测GIS设备局部放电的特征气体;随着局部放电严重程度的加重,SOF2+SO2气体与HF气体体积分数增大,SF6气体分析法比较适用于检测较为严重的放电缺陷;随着SF6气体压强的增大,局部放电产生的SOF2+SO2气体和HF气体的产气速率有下降的趋势。     

火花放电预电离对空气中介质阻挡放电的影响

实现大气压下空气中辉光放电的办法之一是降低空气的击穿场强,避免放电以流注的形式发生.为此,利用脉冲电路产生的火花放电为介质阻挡放电提供初始电子,以验证预电离对介质阻挡放电的作用.实验证明:1. 火花放电预电离确有"点燃"放电,降低空气击穿场强的作用,在正常大气压下,采用预电离手段可使击穿场强降低25%左右;2. 预电离的有效率随气压升高而逐渐减小;3. 在有气体流动的条件下,预电离的作用显著增强;4. 预电离并不是实现大气压下空气中的辉光放电的唯一条件.本文中的方法可以用于在较低场强下提供初始电子以建立均匀介质阻挡放电,但在目前的实验条件下,这种作用还远未达到获得大气压下辉光放电的程度.     

Impulse partial discharge and breakdown characteristics of rod–plane gaps in air and N2 gases

In response to growing environmental concerns, we attempted to develop switchgear without using SF₆ gas. In our research, we used compressed air and pure N₂ as an electrical insulation gas, because of their low global warming potential. In this paper, we examined the impulse breakdown and impulse partial discharge characteristics under various conditions related to nonuniformity of the electric field. The experimental results show that the breakdown voltage (BDV) of air is higher than that of pure N₂ gas under highly nonuniform field conditions in the rod–plane gap. On the other hand, the discharge inception voltage of air and N₂ were almost the same. Furthermore, first partial discharge (PD), leader discharge, and its transition to the breakdown were successfully observed through the measurement of discharge current and light emissions under impulse voltage application. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 148(3): 36–43, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10277     

Change of characteristics of desulfurization and denitrification by combustion flue gas composition and electrode configuration under pulsed corona discharge

Laboratory-scale and parametric experiments of SO₂ and NO_x removal from the simulated combustion gas by pulsed corona discharge have been performed by changing the combustion gas composition and temperature, the electrode configuration of plasma reactor, and the polarity of high-voltage electrode. The following results are obtained: 1) the higher the concentration of H₂O and O₂, the higher the efficiency of desulfurization and denitrification at the same specific input; 2) the pulsed corona discharge with a voltage pulsewidth as short as 200 ns of negative polarity shows the possibility to attain almost 90 percent deSO_x and deNO_x efficiency at the specific discharge input of 20 J/g, which is almost the same as the specific input in the electron-beam process; 3) the deNO_x characteristics show a little temperature dependence in the range of 70 to 130°C, but the deSO_x efficiency increases rapidly in the temperature region below 100°C suggesting the thermochemical dependence of deSO_x reaction; 4) when desulfurization and denitrification proceed, the white dendritic powder deposits on the plasma reactor whose composition is identified to be 49 mol% (NH₄)₂SO₄ and 47 mol% of 2NH₄NO₃ · (NH₄)₂SO₄, and the ratio of SO₂, NO and NH₃ of the deposit is almost equal to that of supplied gas.     

紫外电晕检测仪在电晕放电检测中的应用

首先阐述一种新型紫外电晕检测仪的原理,介绍该仪器目前在国外的应用情况,然后分析该类仪器在系统应用中技术特点和存在的一些问题,最后结合电力系统快速发展的展望了应用的前景。     

沿面型介质阻挡放电的电气特性

沿面型介质阻挡放电在气流控制等方面具有十分广阔的应用前景.本文对其放电机理进行了分析,指出放电过程中在介质板表面积聚的电荷处会形成一虚拟电极,与放电空间其他电荷共同作用,对放电过程产生影响.基于此,建立放电的等效模型,推导了放电功率的计算公式,并与Lissajous图形计算的放电功率比较,具有较好的吻合.讨论了外加电压、频率对放电特性的影响:外加频率相同时,随着外加电压的增加,每半周期内传输的放电电荷不断增大,且其变化趋势与功率增长趋势基本一致,呈非线性增加,同时放电面积增大,功率增加;外加电压一定时,放电功率与频率成正比.     

Laser-guided discharge characteristics of long air gaps and observation of the discharge process

Laser-guided discharge is promising for protection of power transmission systems against lightning. Several experiments concerning the laser-induced electrical discharge have been performed up to now. However, it is necessary to understand the mechanism of the laser-induced electrical discharge to achieve the laser-triggered lightning. When a high-power laser beam is focused in air, a high degree of ionization is produced as brilliant beams near the focus. In this paper, the electrical discharge induced up to 2-meters with a high-power CO₂ laser focused by a 10-meter focal length mirror is described. Experiments of the laser-guided discharge were carried out by application of an impulse voltage to a rod-rod gap after laser radiation. This paper deals with the effects of delay times and polarity of the impulse voltage on 50 percent flashover voltage characteristics and the observation results of discharge phenomena taken by a still camera, a special camera named ALPS (Automatic Lightning Discharge Progressing Feature Observation System) and an image converter camera.     

脉冲等离子体反应器放电特性研究

脉冲放电等离子体被广泛用于气态污染物处理的研究,放电参数直接影响反应器内等离子体状态,进而影响污染物的去除效果,研究不同条件下的放电特性可为脉冲等离子体技术的应用提供参考.本文利用线板式脉冲等离子体反应器, BPFN型高压脉冲电源供电, 研究了电源电容、极板间距及介质阻挡对放电特性的影响.结果表明:增大电源电容可以有效地提高电源能量效率;增大极板间距,峰值电压VP增大,峰值电流IP减小,脉宽减小,波形更加理想;陶瓷板阻挡放电可解决间隙火花放电,使脉冲电晕放电空间分布均匀,在大范围内提高电源能量效率.     

Experimental modeling of high-voltage corona discharge using design of experiments

Many studies, both experimental and numerical, were devoted to the electric current of corona discharge and some mathematical models were proposed to express it. As it depends on several parameters, it is difficult to find a theoretical or an experimental formula, which considers all the factors. So we opted for the methodology of experimental designs, also called Tagushi’s methodology, which represents a powerful tool generally employed when the process has many factors to consider. The objective of this paper is to model current using this experimental methodology. The factors considered were geometrical factors (interelectrode interval, surface of the grounded plane electrode, curvature radius of the point electrode), climatic factors (temperature and relative humidity), and applied high voltage. Results of experiments made it possible to obtain mathematical models and to analyse the interactions between all factors.     

大气压空气辉光放电

重点论述了大气压下辉光放电的研究现状、诊断方法和放电机理,探讨了大气压下空气间隙(>2mm)实现辉光放电的可行性,提出用降低放电电场强度的方法有可能实现大气压下较大空气间隙辉光放电.