防雷接地电阻测量误差分析

通过多年来理论研究和防雷装置检测实践，分析出接地电阻测量误差源原因并总结在不利测量条件下消除或限制测量误差的方法，以求接地电阻测量获得客观准确值。     

4102仪测阻原理及适用范围

介绍了4102型仪器接地电阻测量原理及适用范围、环境要求,分析了测量误差原因及排除办法.     

常见接地电阻测量的误差分析与对策

接地电阻真值是具有唯一性的,因受各种复杂因素的影响,其测量值出现了多个或无穷多个.从理论和实践研究中分析了常见测量误差出现的原因,并提出了在实践中具体解决的方法与对策,以供大家在今后的测量接地电阻中参考.     

4102仪测阻原理及适用范围

介绍了4102型仪器接地电阻测量原理及适用范围、环境要求，分析了测量误差原因及排除办法。     

现行测量接地电阻存在的问题及解决办法

4102接地电阻测试仪作为传统接地电阻测量的常用检测工具,它的工作方式及使用方法使它有时满足不了测量接地电阻时的要求,在测量接地电阻存在一定的局限性.而钳形接地电阻仪作为传统接地电阻测量技术的一大突破,用来测量任何有回路系统的接地电阻,可应用多处并联接地系统,而不需中断待测设备的接地.只要用钳头夹住接地线或接地棒,就能安全、快速测量出对地电阻的特点,很好弥补了4102接地电阻测试仪的缺陷,两者联合起来使用,就会很好解决现行测量接地电阻存在的问题.     

接地电阻随测量电极位置变化的规律及其应用

介绍接地电阻测量常用的两种方法:0.618法和30°夹角法,在实际测量过程中,接地电阻阻值会受到测量环境的影响产生变化,真实的接地电阻阻值测量点不一定在"0.618"或"30°"处。通过改变电压极位置、电流极和电压极与接地极连线的夹角等测量参数,计算理想状态下接地电阻阻值,绘制出接地电阻阻值随不同测量参数变化的趋势图,分析变化趋势,查找出接地电阻阻值随测量参数变化的规律,利用地电阻阻值随测量参数变化的规律选择适合的测量方法或者从一组测量数据中获取真实的接地电阻阻值,提高测量的准确性和科学性。     

接地电阻测量中应注意的几个问题

参照国家有关规范和标准的要求,对接地装置、接地电阻及其测量原理进行分析和总结,指出4102型和摇表式接地电阻仪测量接地电阻时电极的布置方法对测量结果的影响。     

防雷工程中接地电阻的测量

在实际测量中,发现许多接地电阻测量结果相矛盾。为排除导致不正确测量结果的原因,获得准确的测量结果,必须掌握接地电阻的测量要点。第一,选用合适的测量仪器。数字万用表不适用于接地电阻的测量。因为数字式万用表用两点接地法测得的电阻,为两点间的环路电阻,其中包括两点间泥土的电阻;它也不能消除由于存在瞬变电流而引起的误差。因此,必须选用专门用于测量接地电阻的仪器。第二,掌握测量原理。附图为专用测量仪器接线图。该仪器有两个测量回路（电压回路和电流回路）。根据测得的数据,用欧姆定律求出电阻值,即工额接地电阻值…     

埋地金属导体对接地系统电阻测试影响试验分析

搭建试验地网研究土壤中金属导体对接地电阻的影响.通过埋设不同形状金属导体,改变金属导体埋设深度、与试验地网相对距离,在不同点位测量试验地网接地电阻值.分析试验数据发现,埋地金属导体导致接地电阻测量值偏小,其中环形金属导体对接地电阻测量值影响最大,一形金属导体对接地电阻测量值影响最小;金属导体位于测试电压极外侧相比位于内...     

接地电阻测量环境影响机理及其对策

接地电阻是反映防雷装置接地效果的重要技术指标之一,而接地电阻的测量与其环境密切相关.根据电容、电磁场理论,重点分析外界干扰源(高压输电线路、电视发射台或其他基站、地下电缆、轨道等)对接地电阻测量仪影响的机理.结果表明:外界干扰源通过容性耦合、阻性耦合和感性耦合严重干扰接地电阻仪的测量,在此基础上提出了屏蔽法和等电位测量方法是接地电阻测量中防范干扰的有效方法.     

Comparisons of Two Ensemble Mean Methods in Measuring the Average Error Growth and the Predictability

In this paper,taking the Lorenz system as an example,we compare the influences of the arithmetic mean and the geometric mean on measuring the global and local average error growth.The results show that the geometric mean error (GME) has a smoother growth than the arithmetic mean error (AME) for the global average error growth,and the GME is directly related to the maximal Lyapunov exponent,but the AME is not,as already noted by Krishnamurthy in 1993.Besides these,the GME is shown to be more appropriate than the AME in measuring the mean error growth in terms of the probability distribution of errors.The physical meanings of the saturation levels of the AME and the GME are also shown to be different.However,there is no obvious difference between the local average error growth with the arithmetic mean and the geometric mean,indicating that the choices of the AME or the GME have no influence on the measure of local average predictability.     

Comparisons of Two Ensemble Mean Methods in Measuring the Average Error Growth and the Predictability

In this paper, taking the Lorenz system as an example, we compare the influences of the arithmetic mean and the geometric mean on measuring the global and local average error growth. The results show that the geometric mean error (GME) has a smoother growth than the arithmetic mean error (AME) for the global average error growth, and the GME is directly related to the maximal Lyapunov exponent, but the AME is not, as already noted by Krishnamurthy in 1993. Besides these, the GME is shown to be more appropriate than the AME in measuring the mean error growth in terms of the probability distribution of errors. The physical meanings of the saturation levels of the AME and the GME are also shown to be different. However, there is no obvious difference between the local average error growth with the arithmetic mean and the geometric mean, indicating that the choices of the AME or the GME have no influence on the measure of local average predictability.     

雷达测雨及其在水文水资源中的应用研究进展

在回顾国内外雷达网建设和在水文水资源学中发挥重要作用的基础上,着重对国内外的雷达降水的估测算法、雷达临近降水预报和雷达测雨信息在水文模型中的应用研究进行了探讨和分析,并就未来雷达技术应用于水文水资源学的研究进行了展望。     

地面电场仪测量数据的误差来源及分析处理

地面电场仪测量数据准确性和一致性会直接影响到其在研究区域大气电学和进行雷电预警工作的应用准确度。通过模拟理论计算和实际观测数据进行的统计对比分析,指出了电场仪自身高度和周围环境均会产生测量误差,不同高度上的电场测量值与地表处均呈现出一定的正相关性。在晴天和雷暴两种天气情况下,由于产生地面电场的电荷源不同,提出了分别利用统计和线性拟合对这两类测量数据进行修正的方法。     

探空温度传感器受太阳辐射影响的仿真分析

随着高空温度探测精度要求的日益提高,如何减小温度传感器测量误差已成为亟需解决的问题,而太阳辐射作为影响温度传感器探测性能的重要因素已成为该领域研究的热点.利用计算机仿真技术,引入太阳高度角、引线夹角2个影响因子,根据流体动力学模型模拟分析探空温度传感器从海平面上升到32 km高空时所受太阳辐射的影响,最终得到辐射误差与海拔高度的关系曲线族,仿真结果将为开展高空温度传感器误差分析提供基础依据,从而提高传感器测量准确度.     

基于GNSS差分定位的天气雷达坐标精确定位研究

天气雷达天线馈源的精确定位关系到雷达数据的精确使用和天气雷达全网拼图的使用效果.目前,国内新一代天气雷达天线馈源坐标基本都是使用GNSS(GLobal Navigation Satellite System)系统中的美国GPS(Global Position System)系统接收机,在雷达塔楼楼顶单点瞬时定位测量得到的,误差一般大于30 m.为了提高定位精度,将GPS精确定位技术与全站仪测量相对高度结合起来,提出了一种测量天气雷达的馈源坐标的方法,可使天线馈源的海拔高度测量精度达到10 m以内.使用这种方法对北京市气象局S波段新一代天气雷达天线馈源坐标进行了实地测量,精度达到设计要求.     

On the individual calibration of hailpads

This paper is a comparative study between the two most common hailpad calibration systems: one annual calibration of a whole consignment of material, and the individual calibration of each plate after a hailfall. Individual calibration attempts to minimize errors due to differences in sensitivity to the impact of hailstones between plates from the same consignment, or due to differences in the inking process before the actual measurement.The comparison was carried out using calibration data from the past few years in the hailpad network in south-western France, and data from an individual calibration process on material provided by the hailpad network in Lleida (Spain). The same type of material was used in the two cases.The results confirm that the error in measuring hailstone sizes is smaller in the case of an individual calibration of hailpads than when one single calibration process was carried out for a whole consignment. The former is approximately 80% of the latter. However, this error could have been higher if it had not been the same person carrying out the single calibration process and the measuring of the dents: it has been found that differences in the inking process may account for up to 20% of the error in the case of small hailstones. Calibration errors affecting other variables, e.g. energy or parameter λ of the exponential size distribution are generally higher (5% and 18%, respectively) than errors due to the spatial variability of the hailstones. However, the calibration method does not influence the maximum size, since the relative error attributed to the spatial variability is about 8 times the calibration error.In conclusion, if errors in determining energy or parameter λ are to be reduced to a minimum, it is highly advisable to be consistent in applying the measuring procedure (if possible with the same person carrying out the measurements all the time), and even to use individual calibration on each plate, always bearing in mind that technicians have to be trained appropriately in order to achieve the highest possible degree of uniformity.     

JJG自动气象站气象要素计量性能要求合理性探讨

针对自动气象站的温度、雨量对应的检定规程,就其相关指标和规定的合理性进行探讨。目的在于让检定规程更加完善、合理。根据相应仪器本身的特性,结合实际工作经验,以分析误差构成进行理论推导,得出温度（地温）,雨量计量性能要求中最大允许误差等不合理的结果,从误差公式中重新确定了温度、雨量的最大允许误差,分别对规程指标的确定提出了修改建议。     

自动气象站各要素传感器检定结果的不确定度分析

自动气象站是由各要素的传感器和数据采集器组成的。随着时间的推移, 各传感器和数据采集器的测量误差将会发生漂移。为确保各要素观测数据的准确、可靠并具有可比性, 定期开展自动气象站的检定和校准是非常重要的。通过检定将各要素系统误差控制在允许范围内, 并对检定结果进行不确定度分析, 是考察检定结果可信程度的重要步骤。本文依据自动气象站检定规程及JJF1059-1999《测量不确定度评定与表示》的要求, 并根据检定数据, 进行自动气象站的各要素检定结果的不确定度分析, 对自动气象站检定结果可信度评估具有指导意义。