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1.
目前绝大多数气体绝缘开关设备采用SF6气体绝缘,SF6泄漏导致严重的环保问题,人们迫切希望少采用或不采用SF6气体,以降低对环境的污染。为此,试验研究SF6和SF6/N2混合气体在不同混合比、不同压力以及在不同电场结构下的击穿特性,并与SF6气体的绝缘性能进行比较,试验结果表明:在N2中注入20%~30%的SF6气体后,SF6/N2混合气体绝缘性能指标可以达到纯SF6气体的80%左右,但若继续增加SF6气体的配比,则其耐电强度上升的幅度明显变慢;此外,试验研究还发现,极不均匀电场会大大降低气体的耐击穿电压强度。试验研究证明了采用SF6/N2混合气体代替纯SF6气体的技术方案的可行性。  相似文献   

2.
六氟化硫(SF6)气体电气性能良好,但其温室效应严重,使用受到很大限制。通过试验数据对比分析了SF6、N2及干燥空气的理化特性、绝缘性能、分解特性、温升效果,发现干燥空气绝缘性能比N2高10%,但温升效果略低于N2,而N2温升值比SF6温升值高10 K左右。并对比分析了新型环保气体C4-PFN和C5-PFK的理化特性,研究了二者及其混合气体的温升性能及分解特性,给出了各自的应用场合。指出新型环保气体绝缘性能优良,具有良好的应用前景,但存在液化温度高、成本高等问题,对于最佳混合比、气体分子间协同作用有待进一步研究。  相似文献   

3.
在役的大部分气体绝缘金属封闭开关设备(GIS)使用绝缘性能较好的SF6气体作为绝缘介质。为实现“双碳”目标,开展绝缘气体的替代研究以控制SF6气体的使用与排放有助于提升电力设备的环境友好性。为实现SF6/N2混合气体在126kV GIS中的应用,首先确定126kV SF6/N2混合气体型GIS的基本参数,并通过建立各单元的有限元模型进行仿真计算,验证了设计的可行性。型式试验的顺利通过表明,在维持现有GIS结构的前提下,适当混合比及充气压力的SF6/N2混合气体能保证GIS的正常运行。  相似文献   

4.
建立反映气体放电过程中粒子运动特性的二维流体模型,采用有限元和通量校正传输法对该模型进行数值求解,计算了50%SF6+50%N2在均匀电场下的放电规律,模拟了流注发展过程中粒子密度的分布情况,分析放电过程中带电粒子对均匀电场的影响。搭建气体放电实验平台,测量平板电极下绝缘间隙5 mm时SF6/N2混合气体的击穿电压,将SF6/N2击穿电压的实测值与折算值进行对比,研究不同混合比、气体压强对SF6/N2协同效应的影响。结果表明:随着流注向阳极运动,放电间隙内的电子数密度不断增大;在放电初始阶段,空间电荷对电场的影响很小,随着电荷数量不断增加,空间电场产生明显畸变现象。SF6/N2混合气体击穿电压的实验测量值大于折算值,且SF6含量越高,实测值和折算值越接近。可以看出,SF6/N2的协同效应在含有少量SF6时较明显,而当SF6含量较高时,混合气体的协同效应减弱。  相似文献   

5.
为得到新型环保气体HFO-1336mzz(E)应用于气体绝缘输电线路(GIL)中的温升特性,本文基于有限元方法建立磁场-传热场-流体场多物理耦合模型,仿真分析额定工况下GIL内部温度场分布,并研究缓冲气体类型、填充气压、混合比和运行电流对GIL温升的影响。结果表明:额定工况下GIL内部的温度场呈现上高下低的温度梯度分布规律,其中A相导体的温升比B相导体的温升高0.70℃,接地外壳的温升最小。在相同条件下,HFO-1336mzz(E)/CO2混合气体中导体的温升仅比HFO-1336mzz(E)/N2混合气体中的温升低0.38℃,考虑到HFO-1336mzz(E)气体分解后固体析出物的影响,选择CO2作为缓冲气体比N2更为合适。提高填充气压和混合比均能降低导体的温升,填充0.70 MPa的10%HFO-1336mzz(E)/90%CO2混合气体导体的温升仅比填充0.50 MPa纯SF6的温升高5.02℃。GIL导体和接地外壳的温升均随着运行电流的增大而增大,并...  相似文献   

6.
SF6气体是一种极严重的温室气体,在电力设备中被大量使用,如何有效减少SF6气体的使用成为当前的研究热点。本文以SF6/N2混合气体作为研究对象,采用现有145kV三工位隔离接地开关进行SF6气体替代研究。经过试验验证表明,若开关设备的隔板、壳体满足压力要求,使用SF6/N2混合气体能够替代纯SF6气体,可以满足应用要求。  相似文献   

7.
SF6混合气体是广受关注的SF6替代气体方案之一。为定量评估SF6混合气体的灭弧性能,文中采用一维衰减电弧模型和玻尔兹曼方程相结合的方法,将电弧熄灭过程划分为热恢复阶段、弧前介质恢复阶段和弧后介质恢复阶段,分别引入热恢复率、弧前介质恢复率和弧后介质恢复率作为各阶段的评价参数,并计算三者的调和平均数作为综合评价参数,以此来评估SF6-N2、SF6-CO2、SF6-CF4以及SF6-Air混合气体的灭弧性能。基于上述方法,文中初步探讨SF6含量、背景气体种类和压强大小对SF6混合气体灭弧性能的影响。结果表明,随着SF6含量的减少,混合气体的灭弧性能整体上呈现下降趋势;当SF6含量为10%~50%时,4种混合气体中SF6-N2的灭弧性能最优,其次...  相似文献   

8.
六氟化硫/氮气(SF6/N2)混合气体作为六氟化硫(SF6)替代气体被广泛研究,并已在多个电站GIS设备中进行试点应用。在进行GIS设备维护时,迫切需要高效的分离方法来实现混合气体中SF6气体的回收。目前常用的混合气体分离技术主要有液化、低温蒸馏、吸附分离等,但由于分离效率低,并不适用于现场SF6/N2混合气体的分离回收。文中采用膜分离技术,选取玻璃态聚酰亚胺气体分离膜,测试了不同压力和温度条件下SF6和N2的渗透效果,确定了在适宜的温度和压力下,该分离膜的N2/SF6分离选择性可以达到39以上,N2的渗透速率可以达到2.73 GPU以上,具备将SF6和N2分离的能力。在此基础上,测试了单级分离膜分离效果,根据测试结果,选择进入分离膜的气体压力为2.00 MPaG、温度为60℃,设计了三级循环膜分离系统,...  相似文献   

9.
1 100 kV气体绝缘金属封闭输电线路(GIL)中SF_6使用量较大,由于SF_6气体具有很大的温室效应,因此,采用SF6/N2混合气体作为绝缘介质以减少SF6气体的使用量具有重要的社会意义。通过研究SF_6/N_2混合气体的绝缘、温升等特性,提出了适用于1 100 kV GIL的SF_6/N_2混合气体压力及混合比,研制了1 100 kV GIL样机,并进行了绝缘、温升试验研究,试验结果与仿真一致:混合气体压力不变的条件下,气体的绝缘强度随SF_6比例的增加而增大,GIL导体、触指温升随SF_6比例的增加而降低,壳体温升与混合气体中SF_6比例的关系不大;在相同绝缘耐受场强条件下,SF6/N_2混合气体压力与纯SF_6气体压力成正相关关系,且混合气体中SF_6比例越低,气体压力增加的幅度越大。研制的SF6/N_2混合气体绝缘1 100 kV GIL样机通过型式试验及长期带电运行试验,验证了产品长期带电运行的可靠性。  相似文献   

10.
为了研究SF6与不同缓冲气体组成的协同效应,并揭示SF6混合气体的协同效应机理,首先针对SF6气体分别与N2、Air(空气)、CO2、CF4和He组成的混合气体,测试了上述混合气体在SF6摩尔分数0~100%范围下的工频击穿电压,利用Takuma计算公式拟合获得其协同效应系数,发现上述缓冲气体与SF6协同效应的强弱排序为N2>Air>CO2>CF4>He。然后对比了Takuma计算公式与幂函数经验公式的拟合效果,明确了两种方法的适用性。最后通过气体吸附截面分布和缓冲气体电子能量分布分析了不同缓冲气体与SF6协同效应的强弱原因,分析结果与试验结果排序一致,证明了分析方法的合理性,为其他类型混合气体的协同效应研究提供参考。  相似文献   

11.
随着电力需求的增长和环境保护要求的提高,SF6气体的使用逐渐受到限制。SF6混合气体在一定程度上减少了SF6气体用量,目前已经在电气设备中应用。文中针对SF6混合气体在220 kV气体绝缘组合电器(GIS)中发生泄漏引起的绝缘变化展开研究,通过改变微量的气压值和混合比,探究混合气体的绝缘性能变化,分析气压、混合比因素对工频击穿电压的影响规律,获取各气压下各比例混合气体的绝缘强度曲线图,从而得到保证设备安全稳定运行的补气策略。研究发现,混合气体击穿电压的变化规律呈现出随着压强和混合比的提高,非线性程度增大的特点,并且得到了设备安全运行的混合比和气压的边界值。文中的研究可以为SF6/N2混合气体绝缘设备提供运维规程和技术标准,同时为制定混合气体的检测技术标准奠定基础。  相似文献   

12.
Until recently, SF6 gas has widely been used as the best insulating medium in substation equipment. However, SF6 gas was specified to be a greenhouse gas at COP3 in 1997 because of its high global warming potential (GWP), and alternative insulation gases to SF6 have been sought for a long time. Alternatives using the natural gases are considered to be suitable, but none of them show better properties for insulation as well as good environmental compatibility. Therefore, it is necessary to rationalize the equipment insulation level and reduce the test voltage of electric power apparatus to as low a level as possible. The actual lightning surge waveform (so‐called nonstandard lightning impulse waveform) occurring in the actual field is different from the standard lightning impulse waveform (1.2/50 μs). There are many cases in which the actual lightning surge waveform has a steep rise and large decay of overvoltage, and the insulation requirements are not as severe as those for the standard lightning impulse waveform. In this paper, we focused our research on N2 gas as an SF6 substitute and investigated the insulation characteristics of N2 gas for a single‐frequency oscillatory waveform with various frequencies from 2.7 to 20.0 MHz and damping ratios. Based on the experimental results, it might be possible to reduce the test voltage of N2 gas insulation by evaluating the crest value of the actual lightning surge waveform that has been converted into an equivalent standard lightning impulse waveform. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 167(2): 10–20, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20754  相似文献   

13.
SF6 is used as the main insulation gas for gas‐insulated switchgear (GIS), but it has recently become a gas that must be restricted because of its greenhouse effects. To date, we have studied the insulation characteristics of compressed N2 and CO2 as possible alternatives for SF6. We have reported that N2 or CO2 must be pressurized to 2.0 MPa when it is used as a substitute for SF6 at 0.5 MPa. Therefore, we have proposed a hybrid installation composition that uses gas and solid insulators. Because the central conductor of GIS is covered by a solid insulator in this composition, a high‐pressure gas at 2.0 MPa is not needed. However, the joint of the solid insulator becomes a weak point for discharge development. In this paper, we describe an effective configuration for improvement of the withstand voltage based on experiments. The most effective connector was made of resin without an implant electrode and the most effective configuration was one without a solid–solid interface between the solid insulator of the central conductor and the resin connector. In this experiment, the improvement of breakdown electric field of the hybrid composition was 44% or more compared with the case of only gas insulation (conventional method). In addition, further improvement can be expected by optimizing the insulation creepage distance and configuration. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(1): 11–20, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21107  相似文献   

14.
This paper describes partial discharge (PD) inception and breakdown voltage characteristics of a CO2/N2/SF6 gas mixture in a nonuniform field. These voltage characteristics were investigated with ac high voltage by changing the mixture rate of each gas of CO2, N2, and SF6 gas and the gas pressure from 0.1 MPa to 0.6 MPa. It was found that adding a small amount of CO2 gas into a N2/SF6 mixture causes a drastic increase in the breakdown voltage. For instance, when the mixture rate of SF6 in N2/SF6 gas mixture is 50%, with the addition of 1% CO2 the maximum breakdown voltage becomes 1.31 and 1.15 times higher than that of a 50% N2/50% SF6 gas mixture and pure SF6 gas, respectively. Moreover, those voltage characteristics of a CO2/N2/SF6 gas mixture were also investigated by changing the electric field utilization factor as well as by applying positive and negative standard lightning impulse voltages in order to discuss the corona stabilization effect, which seems to be one reason for the drastic increase in the breakdown voltage. These results and breakdown mechanism of the CO2/N2/SF6 gas mixture are discussed on the basis of the corona stabilization effect and the dissociation energies of the component gases by observing PD light images, PD light intensities through a blue and red filter, and PD current waveforms. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(3): 34–43, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10019  相似文献   

15.
SF6 gas has excellent dielectric strength and interruption performance. For these reasons, it has been widely used for gas‐insulated switchgear (GIS). However, use of SF6 gas has become regulated under agreements set at the 1997 COP3. Thus, investigation and development for GIS with a lower amount of SF6 gas are being carried out worldwide. Presently, SF6‐free GIS has been commercialized for the 24‐kV class. Air or N2 gas is used as the insulation gas for this GIS. On the other hand, SF6‐free GIS has not been commercialized for the 72‐kV‐class GIS. The dielectric strengths of air and N2 gas are approximately one‐third that of SF6 gas. To enhance the insulation performance of air and N2 we have investigated a hybrid gas insulation system which has the combined features of providing an insulation coating and suitable insulation gas. We have developed the world's first 72‐kV SF6‐free GIS. This paper deals with key technologies for SF6‐free GIS, such as the hybrid insulation structure, a bellows for the high‐pressure vacuum circuit breaker, a newly designed disconnector and spacer, and prevention of particle levitation. Test results of the 72‐kV high‐pressure air‐insulated GIS with the vacuum circuit breaker are described. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(4): 13–23, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20451  相似文献   

16.
This paper deals with partial discharge (PD) time‐sequential properties of SF6/N2/CO2 ternary gas mixture as well as SF6 and SF6/N2 gas mixture under AC and positive DC voltage applications. The measurements were carried out by changing the gas pressure up to 0.6 MPa and applied voltage with the N‐shape characteristics of breakdown voltage versus gas pressure for each tested gas considered. We obtained experimental results of the gas pressure dependence of maximum peak value of PD current pulse as well as the relationship between the time interval of PD pulses and the peak value of PD pulse. We discuss the mechanism of increase in breakdown voltage by adding CO2 into SF6/N2 gas mixtures in terms of change of PD type from streamer to leader discharge. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(3): 32–40, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20073  相似文献   

17.
The effect of a barrier between a needle electrode and a plane one in an (N2/SF6) gas mixture on creeping flashover was investigated using a microsecond pulse voltage. The SF6 gas content was varied from 0% to 100%, and the gas pressure from 0.1 MPa to 0.3 MPa. The flashover voltage increased with increasing SF6 gas content for a positive needle electrode. For a negative needle electrode, excepting the total pressure of 0.1 MPa, at which similar flashover characteristics were obtained to the positive case, a considerable decrease in flashover voltage was found in the case of a mixture of a few percent SF6 in (N2/SF6) gas mixture at elevated total pressures. The corona behavior on the barrier in (N2/SF6) gas mixture was investigated by means of a high‐speed digital framing camera. © 2000 Scripta Technica, Electr Eng Jpn, 131(1): 1–9, 2000  相似文献   

18.
SF6 gas is widely used in electric power apparatus such as gas‐insulated switchgears (GIS), because of its superior dielectric properties; however, it has been identified as a greenhouse gas at COP3 in 1997, and alternative insulation gases to SF6 have recently been investigated. One of the candidates is CO2 gas, which has lower global warming potential (GWP). However, CO2 gas has a lower withstand voltage level than SF6 gas; therefore, it is necessary to rationalize the equipment insulation level and reexamine the insulating test voltage for electric power apparatus as low as possible. From our previous investigation, in SF6 gas insulation system, we obtained that the insulation requirements of the real surges (called nonstandard lightning impulse waveform) are not as severe as those of the standard lightning impulse waveform. This paper describes the evaluation method for real surges, based on insulation characteristics of CO2 gas gaps. Furthermore, the method was applied to typical field overvoltage waveform in the lightning surge time region for 500‐kV systems and it is obtained that the equivalent peak value of the standard lightning impulse waveform is possibly reduced by 10 to 15%. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(3): 1– 9, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20560  相似文献   

19.
Evaluation of insulation strength for lightning surge that actually enters into substations is important in estimating insulation reliability of gas‐insulated equipment. The standard lightning impulse voltage (1.2/50 µs) is used for factory tests. However, the actual lightning surge waveforms in substations are complex and are usually superimposed with various oscillations. Insulation characteristics of SF6 gas as a function of such complex voltages have not been sufficiently clarified. This paper deals with gap breakdown characteristics in SF6 gas under submicrosecond pulses. Breakdown voltages are lower under a polarity reversal condition than under a monopolarity condition. The cause of this difference is discussed while observing discharge propagation using an image converter camera. The electrode size effect is also discussed. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 18–25, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10246  相似文献   

20.
This paper describes the effect of a barrier on creeping discharge characteristics in SF6, N2, and their mixtures. The barrier height effect on the discharge voltage was investigated under a positive pulse voltage. The discharge voltage increased with increasing barrier height in SF6 gas. On the other hand, the discharge voltage hardly changed with the barrier height in N2 gas. In order to clarify the mechanism of the initial creeping corona, it was observed by optical techniques, including an ultra-high-speed electronic imaging system (IMACON 468). The creeping corona path revealed differences in images at various barrier heights. The accumulated charge induced on the barrier by the initial corona in SF6 gas was able to suppress the development of the later creeping corona, in contrast with N2 gas. © 1998 Scripta Technica, Electr Eng Jpn, 125(4): 1–8, 1998  相似文献   

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