电量变送器发展分析

一、电量变送器的应用和种类电量变送器又称电工测量变送器。它是一种将输入的各种被测电量变换成与其成比例的直流模拟电量的测量装置。它广泛应用于各种远距离监控的电气装置中,其直流电量的输出值通常力0～5V、0～1mA、0～10mA,4～20mA等,以便与系统运动装置、巡回检测装置、自动记录仪、电子计算机等配套组成各种自动化电气监控设备。电量变送器分为直流电流、直流电压、交流电流、交流电压、频率、相位角、功率     

电量变送器

电量变送器是一种高精度的信号转换单元,它能将各种信号(指电压、电流或温度等)变换为归一化的电信号,供远动装置或计算机等使用,也可用于不同的自动化控制系统中。它的输出为直流信号(电压或电流),与输入成比例关系。电量变送器属于低压电器,这一点和其它二次仪表一样。它不能直接承受高电压和大电流。例如3.5千伏或更高、100～400安培。故应首先经仪用电压互感器和电流互感器之类变量器降低后,才能加到电量变送器。因此电量变送器的额定输入值与互感器     

一种校验直流系统交流窜入的新装置研究

按照国家能源局(国能综安全2016-369)《关于做好电网运行的紧急通知》和南方电网(设备2016-46)要求,变电站直流系统需具备交流窜入告警功能,当窜入交流电压大于10V时,将对直流系统正常运行造成危害.本文主要研究一种校验直流系统交流窜入的新装置.     

机械部科学技术进步奖专栏

ZHZ25型便携式电量变送器校验仪(1993年度二等奖)该校验仪是现代电测技术与微机技术相结合的一种用于电量变送器的校验和多功能电气测量的仪表。它采用模拟变换和微处理器技术,实现了交流电压有效值、交流电流有效值、有功功率、无功功率、视在功率、有功电度、无功电度、功率因数、相位和频率等10种电参数的测量。并将电量变送器的     

变压器温控系统校验模拟装置的研究及应用

针对目前变电站在变压器温控系统校验方面存在的问题,研究开发了一种变压器温控系统校验模拟装置,该装置作为培训工具能用于变电站电测工作人员对现场温度表、温度变送器校验工作的培训。装置的应用能显著提升电测工作人员的技术能力及操作熟练度,提高培训效率,使电测工作人员通过模拟操作充分掌握现场温度表、温度变送器的外形结构及工作原理,从而在实际操作中避免操作失误,保障变电站设备运行的安全。     

CPCA系列电容薄膜式绝压变送器校验装置的开发和应用

在核电、食品、半导体等涉及真空测量的行业中,CPCA系列电容薄膜式绝压变送器以其优良的性能,逐渐成为真空测量的主要仪表。各行业对真空测量仪表的需求越来越多,对精度要求也越来越高,随着工艺和技术的不断发展,面对复杂的现场工况,现有CPCA系列电容薄膜式绝压变送器的校验装置的精度和效率已经不能满足真空行业的生产需要。由于绝压变送器真空测量精度的准确高效关乎企业的产量及生产安全,因此研制一种满足要求的高精度、高效率的电容薄膜式绝压变送器的校验装置,彻底解决电容薄膜式绝压变送器校验精度和效率的难题,已经是我国真空行业的迫切需要。本文研制了一种CPCA系列电容薄膜式绝压变送器校验装置,通过对现有的校验装置进行设计改进,在效率、精度等方面有了极大的突破,达到了理想的现场使用效果,彻底解决了绝压变送器校验精度和效率的行业性技术难题。     

轨道交通直流牵引系统继电保护仿真软件的研究

针对轨道交通直流牵引系统的继电保护定值缺乏有效验证手段的问题,提出了开发相应的仿真校验软件。对软件的需求进行了研究,提出了软件的功能构架,结合软件开发、直流短路电流计算及保护定值校验等技术,以软件图形界面设计、短路计算模型的选取和直流馈线断路器保护定值的校验为核心功能模块,实现了轨道交通直流牵引系统继电保护仿真软件的开发。以上海地铁的直流牵引系统为实际应用模型,对软件的仿真结果进行了验证。研究结果表明,该仿真软件能够实现故障模拟及继电保护定值的计算机辅助校验等多项功能,对保护整定值的使用和调整具有指导和验证作用,从而能实现"降低轨道交通直流牵引网继电保护发生误动、拒动概率,提高直流系统运行可靠性"的目标。     

科学技术进步奖专栏

该校验仪是现代电测技术与微机技术相结合的一种用于电量变送器的校验和多功能电气测量的仪表。它采用模拟变换和微处理器技术,实现了交流电压有效值、交流电流有效值、有功功率、无功功率、视在功率、有功电度、无功电度、功率因数、相位和频率等10种电参数的测量。并将电量变送器的模拟输出变换成数字量,由微处理机采集处理及显示,与相应测量变换单元输出相比较,完成误差的计算,并送显示,完成整个校验功能。     

温度变送器的校验和检修

温度变送器的校验和检修张国俊（北京６２１所北京市１０００９５）１温度变送器的校验温度变送器在运行过程中要经常保持清洁、干燥。每运行六个月后，要对其基本性能进行校验，以免出现较大误差。配热电阻的温度变送器校验时的接线图如图１所示。图１变送器校验接线图校...     

高精度光电隔离式直流变送器

高精度光电隔离式直流变送器＊刘永步健康姚仲（南开大学电子科学系天津３０００７１）（天津市电子仪表局）０引言在用计算机实施的过程控制及自动监测系统中需要用变送器将温度、压力、流量变成电流或电压信号,再经Ａ／Ｄ变换送到计算机。为了消除干扰、保护计算机,变...     

基于光纤布拉格光栅和压电转换器的电功率传感器

针对传统功率计测量电功率存在线圈电感、电容与金属部分的涡流感应等限制,本文基于布拉格光纤光栅与压电转换器设计了电功率传感器来测量实功率与虚功率.将布拉格光纤光栅粘贴于压电转换器上,构建了动态应变模拟装置.负载电压与负载电流的乘积形成的等效电压施加在压电转换器上使布拉格光纤光栅动态变化,由此测量光栅动态变化所造成的波长改...     

基于阻抗技术的压电元件自损伤检测-

为了保证结构健康监测系统的有效运行,基于压电阻抗技术原理,提出了一种压电传感、驱动元件自损伤检测方法.通过研究压电元件等效电容值(压电元件导纳虚部数值)的变化,判别压电元件是否破损及其与主体结构之间是否剥离,并在悬臂梁结构上进行压电元件自损伤检测试验.结果表明,相比压电元件完好的情况,各频率下压电元件电纳值随脱粘部分面积的增加而上升,随破裂部分面积的增加而下降,并且损伤程度和等效电容变化量成比例关系,与理论分析结果吻合较好.     

压电换能器装配液压扭矩扳手设计

针对压电换能器传统装配中存在的扭矩不稳定和大批量装配时不能保证统一性与准确性的问题,分析了液压扭矩扳手结构特点及其关键设计,提出了压电换能器装配液压扭矩扳手的具体方案。研究结果表明,该方案实现了大批量压电换能器装配扭矩恒定的要求,也为大批量恒扭矩装配压电换能器奠定了基础。     

级联型多电平逆变器单元电路数字化控制的研究

本文分析了双向直流变换器的工作情况,设计了以DSP为控制核心的闭环控制系统,发挥FPGA硬件速度快、稳定性好的特点设计了移向PWM模块,改变了DSP程序产生移相PWM波的方法,大大提高了系统的适时性,为其应用于级联型多电平逆变器四象限运行奠定了基础。实验表明开关管实现了零电压开通,变换器整体效率达94.2%,具有实用价值。     

Inter-laboratories comparison at 100 GΩ and 1 TΩ level to evaluate the traceability transfer from INRIM in the field of high dc resistance

A National inter-laboratories comparison of dc resistance at 100 GΩ and 1 TΩ among the National Institute of Metrological Research (INRIM) and eight Secondary Electrical Calibration Laboratories was carried out in 2010. All the involved Laboratories made their measurements with a method based on a Multifunction Calibrator (MFC) and on a digital multimeter (DMM), both used in their dc voltage function.These and other Secondary Electrical Laboratories are traceable to National Standards by means of the calibration at INRIM of a complete set of primary standards or, alternatively, by means of the calibration of a high accuracy DMM or of a Multifunction Transfer Standard (MTS) or of few primary standards. All the relative differences between each Laboratory’s value and its reference value obtained in the comparison were within their relative expanded uncertainties. This result showed that the traceability transfer methods from INRIM to Electrical Secondary Laboratories lead to satisfactory results in the field of high dc resistance.     

基于虚拟仪器的PID温室远程控制系统的设计

针对目前温室面积不断增大、温室内传感器种类及数量不断增多等情况,利用虚拟仪器软件开发平台LabVIEW,设计出PID温室远程智能控制系统。此系统由温室内各类传感器得到非电量转化为随环境参数改变的电量,然后用虚拟仪器对输入到数据采集卡的电信号进行实时采集,实现对温室环境参数数据远程显示、存储、统计、控制等。通过控制不同时期作物生长所需要的最佳环境参数,实现了温室的智能化管理。     

Traceability of electrical quantities obtained by sampling

The substitution of the traditional analogic measurement and processing techniques with sampling methods is a trend in modern metrology. Many commercial instruments perform this determination by means of their internal firmware. An analysis is necessary when sampling instruments are employed within a laboratory, for the determination of one or more quantities. However, this analysis is possible only under some specific circumstances, where both the characteristics of the samples and the processing algorithms have to be known.The paper will consider the samples as input for the determination of given quantities and the methods to evaluate the uncertainty of the results from the uncertainty of the samples and their correlation. The example is derived by the uncertainty evaluation of the INRIM system for the precision measurement of the power, where the determination of the accuracy has been accomplished both by an almost analytical approach followed by a numerical evaluation.     

80Mn14钢中Mn含量对开坯咬入条件的影响

在轧制工艺一定的条件下 ,对 80Mn14钢按冶炼化学成分C、Si、Mn含量的不同 ,分组进行了轧制 ,得出了Mn含量在80Mn14钢中的变化是影响开坯咬入条件变化的主要因素这一结论 ,为 80Mn14钢既能满足协议标准范围内的冶炼生产、又能顺利开坯指明了Mn含量的合理范围     

A multilayer transducer that contains piezoelectric layers

Formulas for the transfer functions and electric resistance for transducers that consist of an arbitrary number of active (piezoelectric) and passive layers are obtained. Parallel and series electrical connections of layers are considered. Formulas for reducing any active layer to a passive one are obtained. On the basis of the analysis of the obtained expressions and presented calculation results, recommendations for the practical use of the considered transducers are expounded. The obtained data allow the development of transducers with appreciably improved characteristics in comparison to the case where only one active element is used. The proposed new calculation method makes it possible to substantially simplify the determination of formulas for an arbitrary number of layers. The formulas for the main functions of a transducer concern multiple three-sided transducers, on one side of which certain conditions for their electrical connection are imposed. The transfer functions for the reception mode with respect to the voltage at the working surface of the transducer are obtained. The proposed calculation method can be also applied to other types of transducers.     

PULSE DISCRIMINATION FOR ELECTRICAL DISCHARGE MACHINING WITH ROTATING ELECTRODE

This article presents a new method for discrimination of various types of pulses generated during an electrical discharge machining process in presence of a rotating electrode. Existing pulse discrimination methods do not perform efficiently in an electrical discharge machine with rotating electrode, as arcs rarely occur during the machining process. Our method involves simultaneous comparison of the gap voltage and current signals with various thresholds. The main advantage of our proposed method is its efficient computation and significantly better accuracy in discriminating between various pulse classes for electrical discharge machining devices with rotating electrode. Experimental studies demonstrate a superior performance of our method in distinguishing normal pulses from harmful arcs, open circuit and short circuit pulses, compared with the state-of-art methods.