电涌保护器级间退耦元件的选型分析

针对电涌保护器（SPD）级间能量配合试验中配合失效的问题,主要利用波的传输理论与基尔霍夫定律进行分析,结合JB/T 10618-2006（组合式电涌保护器）的规定假设一套组合型SPD,通过基础理论分析与精确计算得出：当被保护装置属于低频（直流）设备时,在不影响信号强度的情况下,退耦元件采用电感或电阻型元件均可;当被保护装置属于高频设备时,退耦元件只能选用低电感量的电阻型退耦元件.退耦元件的参数值均可按照波的传输理论与基尔霍夫定律进行理论计算.这在组合型SPD退耦元件的选型过程中,具有重要的指导意义.     

MOV通流能力衡量优化方法

MOV作为压敏型电涌保护器(SPD)的主要防雷元件,依据IEC 61643的规定,其通流能力是反映SPD防雷性能的重要指标,故通常用标称(最大)放电电流来衡量MOV通流能力,但这并不意味着MOV的标称放电电流就是衡量MOV的通流能力最佳参数,为了更为准确地研究SPD的防雷性能,需要对MOV通流能力的衡量方法进行进一步优化分析。通过详细分析通流能力的本质含义,引入能量资源(安秒资源)的概念,区分了MOV的标称(最大)放电电流与通流能力的关系,结果显示:利用MOV的能量资源(安秒资源)来体现器件的通流性能,更符合MOV的特征,优化后的衡量方法对于SPD防雷性能的精确定标具有重要的参考价值。     

十脉冲下限压型SPD级间串联退耦电感前后能级匹配研究

退耦电感是限压型浪涌保护器(SPD)级联配合核心元件,对于限压型SPD能级匹配具有重要影响.针对退耦电感与限压型SPD能级匹配问题,基于行波传输理论建立多级限压型SPD能量匹配模型,并结合更接近自然雷击的10个8/20 μs多脉冲试验进行研究,试验结果可知:恒定波阻抗下,增大SPD线路间退耦电感值,可有效减缓雷电瞬态过...     

复合型电源防雷器放电通道的探讨及产品应用

引言 复合型电源防雷器(SPD)是基于开关型空气间隙和限压型压敏元件零距离组合而成的防雷产品,它具有结构紧凑、性能可靠、适应窄小环境安装等优点.国内外此类产品目前已广泛应用于空间距离有限,需要多级防雷的场所,如加油站,电信基站等.     

在低压配电系统中采用SPD接线方式应注意的问题

从防雷工程设计施工实践出发,按照国内外相关防雷技术标准中的规定,对TN和TT系统这两种主要接地制式的低压配电系统中不同SPD接线方式进行了分析。结果表明,TT制低压配电系统适宜采用“3 1”保护模式的SPD接线方式;对于有剩余电流保护器(RCD)的TT制低压配电系统,“4 0”保护模式的SPD只能安装在RCD负荷侧或采用“3 1”保护模式的SPD;对于SPD的接地独立于配电系统接地的TN制低压配电系统,其SPD的安装应将TN系统视为TT系统。     

小议电源防雷器(SPD)的安装

对电源防雷器(SPD)的类型以及设备的使用情况和电源的制式、电源的线径与电源防雷保护器安装的距离和接地方面进行阐述,只有正确地选择、配置、安装才能使SPD达到预期的效果.     

电源SPD安装、使用问题的探讨

文章介绍了低压配电系统防雷保护方案设计中所遇到的SPD安装位置、SPD间的配合、SPD保护模式等问题,以及SPD安装中的注意事项和SPD的日常检查维护。     

新建筑防雷装置设计中存在的问题

总结了在山东省的防雷施工图设计说明和防雷装置设计中普遍存在的问题,设计说明中存在的问题主要包括:引用规范不全面、防雷类别标注不准确、避雷带材料标注不明确、SPD参数不明等.防雷装置设计中存在的问题主要是:(1)未充分考虑建筑物屋面特点,造成安全隐患; (2)未设计SPD的各种技术参数.     

UPS防雷问题探讨

分析了内部安装防雷元件和没有安装防雷元件的UPS遭受雷击的原因.雷电感应过电压是造成UPS遭受雷击的主要原因.UPS的雷电防护措施,重点在于电源线路的防护,应采取合理设置SPD、屏蔽、接地和等电位连接等措施,保障UPS在雷雨季节能真正起到不间断供电的作用.     

雷电脉冲下金属氧化物压敏电阻并联的性能分析

金属氧化物压敏电阻(MOV)是电涌保护器(SPD)的核心部件,为了提高SPD的通流量,厂家通常采用MOV并联的方式。为了研究MOV并联的耐压性能,本文利用组合波发生设备,分别对单片MOV与双片并联MOV加载雷电脉冲。研究发现:并联组合的MOV的残压比单片MOV要低;并联组合MOV保护水平高于单片MOV;保护水平的不同是MOV的电流偏差引起的;对MOV均流性并联能尽量降低电流偏差。     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi region.     

IMPACT OF ATMOSPHERIC LOW-FREQUENCY OSCILLATION ON THE IMMIGRATION OF NILAPARVATA LUGENS(STL) IN HUNAN AND JIANGXI PROVINCES

Various features of the atmospheric environment affect the number of migratory insects, besides their initial population. However, little is known about the impact of atmospheric low-frequency oscillation(10 to 90 days) on insect migration. A case study was conducted to ascertain the influence of low-frequency atmospheric oscillation on the immigration of brown planthopper, Nilaparvata lugens(Stl), in Hunan and Jiangxi provinces. The results showed the following:(1) The number of immigrating N. lugens from April to June of 2007 through 2016 mainly exhibited a periodic oscillation of 10 to 20 days.(2) The 10-20 d low-frequency number of immigrating N. lugens was significantly correlated with a low-frequency wind field and a geopotential height field at 850 h Pa.(3) During the peak phase of immigration, southwest or south winds served as a driving force and carried N. lugens populations northward, and when in the back of the trough and the front of the ridge, the downward airflow created a favorable condition for N. lugens to land in the study area. In conclusion, the northward migration of N. lugens was influenced by a low-frequency atmospheric circulation based on the analysis of dynamics. This study was the first research connecting atmospheric low-frequency oscillation to insect migration.     

A COMPARATIVE ANALYSIS OF ATMOSPHERIC AND OCEANIC CONDITIONS BEFORE THE OCCURRENCE OF TWO TYPES OF EL NIO EVENTS

The atmospheric and oceanic conditions before the onset of EP El Ni?o and CP El Ni?o in nearly 30 years are compared and analyzed by using 850 hPa wind, 20℃ isotherm depth, sea surface temperature and the Wheeler and Hendon index. The results are as follows: In the western equatorial Pacific, the occurrence of the anomalously strong westerly winds of the EP El Ni?o is earlier than that of the CP El Ni?o. Its intensity is far stronger than that of the CP El Ni?o. Two months before the El Ni?o, the anomaly westerly winds of the EP El Ni?o have extended to the eastern Pacific region, while the westerly wind anomaly of the CP El Ni?o can only extend to the west of the dateline three months before the El Ni?o and later stay there. Unlike the EP El Ni?o, the CP El Ni?o is always associated with easterly wind anomaly in the eastern equatorial Pacific before its onset. The thermocline depth anomaly of the EP El Ni?o can significantly move eastward and deepen. In addition, we also find that the evolution of thermocline is ahead of the development of the sea surface temperature for the EP El Ni?o. The strong MJO activity of the EP El Ni?o in the western and central Pacific is earlier than that of the CP El Ni?o. Measured by the standard deviation of the zonal wind square, the intensity of MJO activity of the EP El Ni?o is significantly greater than that of the CP El Ni?o before the onset of El Ni?o.     

全球贸易隐含碳变化及其影响分析

基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。     

Analysis of Atmospheric Boundary Layer Height Characteristics over the Arctic Ocean Using the Aircraft and GPS Soundings

正ERRATUM to: Atmospheric and Oceanic Science Letters, 4(2011), 124-130 On page 126 of the printed edition (Issue 2, Volume 4), Fig. 2 was a wrong figure because the contact author made mistake giving the wrong one. The corrected edition has been updated on our website. The editorial office is sincerely sorry for any     

Index to Vol.31

正AN Junling;see LI Ying et al.;(5),1221—1232AN Junling;see QU Yu et al.;(4),787-800AN Junling;see WANG Feng et al.;(6),1331-1342Ania POLOMSKA-HARLICK;see Jieshun ZHU et al.;(4),743-754Baek-Min KIM;see Seong-Joong KIM et al.;(4),863-878BAI Tao;see LI Gang et al.;(1),66-84BAO Qing;see YANG Jing et al.;(5),1147—1156BEI Naifang;     

Information for Contributors

正Journal of Meteorological Research is an international academic journal in atmospheric sciences edited and published by Acta Meteorologica Sinica Press,sponsored by the Chinese Meteorological Society.It has been acting as a bridge of academic exchange between Chinese and foreign meteorologists and aiming at introduction of the current advancements in atmospheric sciences in China.The journal columns include Articles.Note and Correspondence,and research letters.Contributions from all over the world are welcome.