浅析气体分解产物检测应用技术

气体绝缘设备中SF6气体分解产物检测为设备故障诊断提供了有效依据,本文对SF6气体分解产物的检测技术、试验研究及其在设备故障诊断应用等方面的国内外研究现状进行了综述,结合设备状态评价的需求,以期得到设备故障诊断的SF6气体分解产物判据,及气体绝缘设备的运行管理.     

六氟化硫气体分解产物分析对气体绝缘开关设备（GIS）潜伏性故障判断的应用

六氟化硫（SF6）气体在电弧、电火花和电晕放电的作用下会发生分解,产生二氧化碳（CO2）、四氟化碳（CF4）等分解产物。SF6气体组分分析（可在设备带电状态下进行）是诊断SF6气体绝缘设备内部运行情况的一个强有力的手段,据此可判断设备是否故障,并确定故障的具体部位,近年来已有不少成功案例,但判断电气设备潜伏性故障的经验不多。本文总结了广东省部分变电站组合电器（GIS）气室中SF6分解产物的含量,并进行SF6组分分析,为SF6GIS潜伏性故障及其故障类型判断累积经验。     

基于SF_6分解特性的电力设备绝缘缺陷检测方法

搭建SF6GIS电力设备试验平台,分别设置尖端电晕、悬浮电位及绝缘子沿面等三种绝缘缺陷,研究GIS中典型绝缘缺陷下的SF6气体分解特性,同时针对现场案例进行应用分析。试验结果显示,SF_6气体的分解特性与绝缘缺陷的类型密切相关,尖端电晕及悬浮电位缺陷下检测到的主要分解产物包含SO_2F_2,S_2OF_(10)和SO_2,其中,S_2OF_(10)在悬浮电位缺陷下的含量明显高于尖端电晕缺陷,可以利用产物含量比值φ(S_2OF_(10))/φ(SO_2F_2)对这2种缺陷进行识别。绝缘子沿面缺陷条件下能检测到CF_4,CS_2等含碳产物以及较高含量的SO_2。现场应用案例显示,SF_6气体产物检测法是一种诊断GIS内部绝缘缺陷的有效方法。     

基于气体检测和模糊Petri网的GIS故障诊断方法

考虑到GIS设备绝缘故障的多样性、复杂性,以及故障征兆的模糊性、关联性,将气体检测法与模糊Petri网相结合,应用于GIS故障诊断,可有效区分GIS局部放电类型。首先,分析SF6在局部放电下的分解机理,描述故障征兆与GIS绝缘故障之间的关系;其次,将气相色谱仪检测得到的特征气体作为模糊Petri网的输入库所,建立基于SF6气体检测和模糊Petri网的GIS绝缘故障诊断模型,利用模糊Petri网,并行推理分析GIS绝缘缺陷类型的置信度。最后,实验分析验证所提方法的正确性和有效性。     

气体杂质对SF6气体分解产物影响研究

摘要：对SF6气体内的氮气、水分、氧气和四氟化碳4种气体杂质在放电情况下对SFe气体分解产物的影响进行了详细的试验研究。结果表明,在低能量放电情况下,氮气和四氟化碳含量变化对SF6气体分解产物影响较小,水分和氧气杂质能促进SF6气体分解产物的生成。研究结果为通过SF6分解产物判断设备故障提供参考。     

Rh掺杂质单壁碳纳米管表面NO吸附反应的第一性原理研究

由于局部放电,SF6∕N2混合气体会发生分解.基于密度泛函理论研究SF6∕N2混合气体的一种分解产物NO对铑掺杂单壁碳纳米管表面的气敏特性.模拟和分析了NO气体靠近铑掺杂SWCNT(8,0)表面的吸附结构、吸附能量、电荷转移量、态密度等.结果表明,NO在Rh-SWCNT上的吸附过程是放热的.根据DOS分析,NO气体吸附在Rh-SWCNT表面后,NO与Rh-SWCNT的相互作用力变强,共价性增加.分析得出Rh-SWCNT材料可能适合作为检测SF6∕N2气体绝缘设备中NO的气体传感器.     

SF_6气体分解产物现场检测技术的研究及其应用

文章介绍了SF6气体分解产物现场检测技术,包括检测管法、红外光谱法、气相色谱法、光声光谱法等,并分析了各种检测方法的不同,结合现场实际检测的需要,研发了一台SF6气体质量综合检测仪,确保SF6电气设备的安全运行。     

不同温度下环保型HFO-1234ze(E)/CO2混合气体分解机理

由于SF6气体的温室效应,以C4F7N、C5F10O、C6F12O和HFO-1234ze(E)等气体为代表的新型环保替代气体得到了广泛的关注,但对于这些气体分子在局部过热或放电状态下导致设备内部温度升高时的分解机理还缺乏研究,为了进一步探究新型环保气体替代SF6气体的可行性。本文以HFO-1234ze(E)分子为例,基于ReaxFF反应分子动力学方法和密度泛函理论,从微观层面模拟研究了HFO-1234ze(E)分子和不同温度下20%HFO-1234ze(E)/80%CO2混合气体的分解现象。结果发现：HFO-1234ze(E)分子存在着7种不同的分解路径,且CO2中的C=O会最先分解,而HFO-1234ze(E)中的C-F键和C=C双键焓值较高,断裂较为困难,随着温度的升高,发生分解的时间也越早;当温度低于2000K时,HFO-1234ze(E)/CO2混合气体几乎都不会发生分解,但当温度为2000K时,HFO-1234ze(E)分子不会发生分解,但CO2分子会迅速发生分解,2600K以上时,温度每上升2000K,HFO-1234ze(E)就会多分解5个左右,CO2就会多分解35个左右,直到最后基本完全分解。混合气体主要分解产生CO、O2、C2O2、HF、CF4、C2F6、C3F6和C3H3F3等各类自由基,其中CO为有毒气体、HF为强腐蚀性气体,应采取措施对其含量进行监测,其他分解产物的化学性质均较为稳定且对环境无害,并仍然具有一定的绝缘能力,表明20%HFO-1234ze(E)和80%CO2混合气体在一定程度上可以完全替代SF6气体,这也为进一步研究其他新型环保混合气体提供了理论依据和工程指导。     

智能变电站SF6气体密度及微水状态在线监测应用研究

SF6气体现阶段被广泛应用于高压电气设备中,在正常工况下,具有良好的绝缘性能和灭弧性能,是较为理想的绝缘及灭弧介质。但在电弧和电晕的作用下,SF6气体会分解,产生剧毒的低氟化合物,这些化合物会导致沿面的绝缘材料和金属表面恶化,引起绝缘材料的损坏。SF6的分解反应与水分有很大关系,其工作气压和微水含量的高低对设备的安全可靠工作具有直接的影响,如果SF6气体泄漏导致密度下降或气体中微水含量超标,高压电气设备就会存在安全隐患甚至导致事故发生。因此对SF6高压电气设备气体密度和微水含量的监测一直是相关行业对设备监测的一个重要的组成部分。     

电气设备中混合绝缘气体检测技术研究

随着SF_6混合绝缘气体在电力行业中的应用,相应的检测技术成为目前的研究重点之一。文章从混合比、湿度、泄漏和分解产物四个检测方面,系统性阐述了目前混合绝缘气体的检测技术研究进展。同时在现有的SF_6检测技术的基础上,对SF_6混合绝缘气体检测技术进行探究,并提出相应的方案,为混合绝缘气体的推广提供有力的技术支持。     

环保型高压电力开关设备研究进展综述

六氟化硫(SF₆)是一种强温室效应气体,其全球变暖潜能指数(GWP)为二氧化碳的23900倍,且大气寿命为3200年, 被广泛应用于高压开关设备,SF₆的大量使用给温室效应问题带来了巨大的潜在威胁,限制其在电力开关设备中的使用是促进绿色电力工业发展的有效途径。近年来,国内外对基于去SF₆技术的环保型开关设备开展了大量的研究,本文总结回顾了基于SF₆替代气体和真空开断+洁净空气两种环保型开关设备研究进展。首先,分析了环保气体绝缘高压开关设备中的关键技术,介绍了SF₆替代气体C₄F₇N、C₅F₁₀O、全氟化碳类气体(c-C₄F₈、C₃F₈、CF₄)、CF₃I、HFO类气体,从替代气体的绝缘性能、开断性能及分解特性三方面阐述了环保气体绝缘开关设备的研究进展,并在此基础上分析了环保气体绝缘开关设备产品现状及发展趋势。其次,对真空开断+洁净空气的关键技术进行了阐述,总结了大电流真空电弧磁场控制技术、分、合闸曲线特性研究、真空绝缘技术、真空灭弧室外绝缘、快速真空开断技术和真空断路器X射线泄露研究现状,在此基础上总结了真空开断型环保电力开关设备现状及其未来发展趋势。最后,基于环保电力开关设备向更高电压等级、更大短路电流发展的需求,进一步指出未来可能面临的相关技术难点,以期对未来环保型电力高压开关设备的开发提供参考。     

GIS局部放电的SF_6分解物的检测方法

SF6分解物检测技术在检测局部放电方面,具有抗干扰能力强、精度高、可在线监测等优点,具有良好应用前景.从检测原理到检测手段,介绍了SF6分解物检测的各种方法,着重对各种方法的优缺点进行了归纳和横向比较,并对存在的一些关键问题进行了分析与讨论.     

三相联动双断口户外高压隔离负荷开关的研究

为了解决目前农村电网和郊区电网广泛使用的高压柱上开关产品存在的问题，如容易受恶劣环境影响、SF₆气体排放等，设计了一种新型三相联动双断口户外高压隔离负荷开关。采用环氧树脂固体绝缘和硅橡胶外包绝缘技术，具有耐高低温、耐紫外线和耐老化等优势。同时，采用小型化弹簧操作机构和挂簧传输方式以提高设备可靠性。此外，该开关内嵌真空灭弧装置，无需使用SF₆气体绝缘，对环境更为友好。与传统设备相比，所设计的隔离负荷开关采用双真空开关和三相柱式倒装结构，具备无污染、安全可靠、长寿命和低成本等优点，为实现高压线路的有效管理和维护提供了一种新的解决方案。     

便携式气相色谱检测技术在特高压工程调试阶段的应用

采取加装FPD检测器、优化试验条件等措施,对现有的便携式气相色谱检测技术进行改进,能检测出更多种类的分解产物,同时具备较高的分离和检测效率。在特高压工程六氟化硫电气设备调试阶段,运用该项技术可以快速准确地对疑似故障设备内SF6气体分解产物进行检测,有助于对故障位置、类型和严重程度进行准确判断。     

低温等离子体吸附两段式系统降解硫化氢

为了克服单一低温等离子体(NTP)降解硫化氢(H₂S)能耗高和副产物排放的问题,采用低温等离子体活性炭纤维(ACF)吸附两段式系统降解硫化氢,考察不同充电电压两段式系统与单一低温等离子体系统对H₂S降解率及副产物的影响,分析低温等离子体与活性碳纤维协同降解硫化氢的机理.研究表明：两段式系统能够显著提高H₂S的去除率、降低能耗、去除副产物,并能延长ACF的穿透时间,增加吸附反应H₂S的容量.当气体流量达到11.8 m³/h、充电电压为6 kV时,两段式系统能使H₂S的去除率提高15%,能耗节省26.5%,ACF能够有效地去除SO₂和O₃,在ACF穿透前气流出口检测不到污染物;当充电电压从3 kV升高到7 kV时,ACF的穿透时间延长2到16倍.     

Research and application of an intelligent recloser controller installed on outdoor rod

A new type of intelligent recolser controller installed on the outdoor rod is developed, which is mainly composed of microcontroller of Intel 87C196KC-20 and CPLD devices. This controller integrates all the functions of measuring, controlling, protection, fault diagnosis, communication, remote-controlled operation and self-power devices with infra-red remote control devices as a unit. The controller applies the distributed structure, field concentration line and intelligent technology to seal up the synthetic servomechanisms such as the microcomputer-based protection and measuring devices in the second stage of the mini out-door transformer substation, which are distributed on the outdoor circuit switches on the spot and formed as a whole. Therefore,this technology can transform a large number of ordinary homemade SF6 circuit beaker and vacuum circuit breaker into intelligent circuit recloser, thus replacing the expensive imported automatic circuit recolser.     

CFD model simulation of bubble surface area flux in flotation column reactor in presence of minerals

Bubble surface area flux(S_b) is one of the main design parameter in flotation column that typically employed to describe the gas dispersion properties, and it has a strong correlation with the flotation rate constant. There is a limited information available in the literature regarding the effect of particle type,density, wettability and concentration on Sb. In this paper, computational fluid dynamics(CFD) simulations are performed to study the gas–liquid–solid three-phase flow dynamics in flotation column by employing the Eulerian–Eulerian formulation with k-e turbulence model. The model is developed by writing Fortran subroutine and incorporating then into the commercial CFD code AVL FIRE, v.2014.This paper studies the effects of superficial gas velocities and particle type, density, wettability and concentration on Sband bubble concentration in the flotation column. The model has been validated against published experimental data. It was found that the CFD model was able to predict, where the response variable as indicated by R-Square value of 0.98. These results suggest that the developed CFD model is reasonable to describe the flotation column reactor. From the CFD results, it is also found that Sb decreased with increasing solid concentration and hydrophobicity, but increased with increasing superficial gas velocity. For example, approximately 28% reduction in the surface area flux is observed when coal concentration is increased from 0 to 10%, by volume. While for the same solid concentration and gas flow rate, the bubble surface area flux is approximately increased by 7% in the presences of sphalerite.A possible explanation for this might be that increasing solid concentration and hydrophobicity promotes the bubble coalescence rate leading to the increase in bubble size. Also, it was found that the bubble concentration would decrease with addition of hydrophobic particle(i.e., coal). For instance, under the same operating conditions, approximately 23% reduction in the bubble concentration is predicted when the system was working with hydrophobic particles. The results presented are useful for understanding flow dynamics of three-phase system and provide a basis for further development of CFD model for flotation column.     

Catalytic Decomposition of Nitric Oxide by LaCoO<Subscript>3</Subscript> Nano-particles Prepared by Rotary CVD

Catalytic direct decomposition of NO by perovskite-type catalysts has attracted much attention for the various possible components and the unique structure. LaCoO₃ nanoparticles were precipitated on α-Al₂O₃ micro powders by rotary chemical vapor deposition (rotary CVD) and its catalytic performance for the decomposition of NO was investigated. LaCoO₃ nano-particles with 100 nm in average diameter and 1.5% in mass were uniformly dispersed on α-Al₂O₃ powder. The conversion of NO increased with increasing temperature from 400 to 950 °C, and reached 28.7% at 950 °C. The gas velocity of transformed NO on LaCoO₃ nano-particles catalyst per mass unit was 7.7 mL/(g min), showing a good catalytic activity over the calculated results of pure catalysts. After five times of aging performance experiments, the NO conversion kept the same value, showing a good aging performance and thermal stability.     

Photocatalytic activity of porous magnesium oxychloride cement combined with AC/TiO<Subscript>2</Subscript> composites

As a decorative material, magnesium oxychloride cement was used as a photocatalyst supporter to purify the pollutants indoors. Due to excellent adsorption properties of activated carbon (AC), the photocatalytic composties, TiO₂/AC, were prepared and introduced into the porous magnesium oxychloride cement (PMOC) substrate to composite a sort of photocatalytic cementitious material (PCM). The optimal composite processes were assessed by gas chromatograph, using toluene as the target. By comparing the perspective of toluene purification and thorough decomposition, it can be found that the optimal mass ratio for TiO₂/AC composites is 4/25, and the heat treatment to TiO₂/AC sample at 350 °C can play the optimal synergetic role of adsorbents in photocatalytic process. The synergistic effect of TiO₂, AC and magnesium oxychloride cement (MOC) was also evaluated by gas chromatograph. One-take molding process was adopted to introduce the TiO₂/AC into PMOC substrate, and its optimal mass fraction was 4 wt%, while the appropriate density of substrate was 0.35 g/cm3. Toluene degradation showed that the prepared PCM can degrade pollutants efficiently. The appropriate treatment process of TiO₂/AC, mass of TiO₂/AC, substrate density, and stable pore structure should be coordinated to maximize the adsorption-photodegradation performance. The combination of photocatalytic materials, adsorbents, and building materials provided a new idea for the application of photocatalysis.     

SF_6/N_2混合气体绝缘特性的试验研究及理论分析

应用自制的试验模型对SF6/N2混合气体的绝缘能力进行了试验研究,并和纯净的SF6、N2的绝缘能力进行了比较,获得了SF6/N2混合气体在不同比例下的击穿电压与气体间隙距离之间的曲线.经综合比较、分析确定50%SF6 50%N2的混合气体的经济技术指标比较高,可以在电气设备中作为绝缘介质广泛应用.