变电站 10kV、35kV 系统电容电流测试研究

随着电网规模的不断扩大，测试电容电流是否超过标准显得十分重要，本文探讨了电容电流的测试方法及原理，通过对现场测试所遇到的问题和困难，提出了相应的解决措施，并分析了部分变电站电容电流的数据，为进一步的电容电流数据的测试指明了方向。     

预制分支电缆传输特性分析

线性边界元法(LBEM)是在常数边界元法(CBEM)的基础上,从线性插值函数出发将边界单元按线性分布来进行处理的一种数值方法。文章推导出二维静电场边值问题的线性单元的边界元方程,电容及特性阻抗计算公式。以外方内圆同轴传输线为例,计算结果表明用线性边界元方法计算二维场域问题是有效可行的。并用同一线性边界元法通用程序对分支电缆进行计算,所获耦合电容为加工制作提供了理论参考。     

不对称三绕组单相异步电动机的优越性及其电磁计算程序

洗衣机用电容电动机通常有两个绕组,其平均效率仅为52％。新的研究表明:采用三绕组的电容电动机比两绕组电容电动机更为优越,在同等材料消耗条件下效率可达60％以上;而在达到同样性能条件下材料消耗可减少10％。本文探讨了三绕组电容电动机设计程序中的一些特殊问题。在分析中采用了新发展起来的合成电流法,它比传统的对称分量法更为简便。     

电容式均匀度仪测试准确性的探讨

电容测试方法应用广泛，但测试结果有一定误差。本文对电容检测方法的原理进行了探讨，指出了该方法在某些条件测试的不准确性和使用局限性，并提出了影响测试结果的因素。     

基于开关电容技术的8阶切比雪夫滤波器及PSpice仿真研究

应用开关电容电路技术对8阶切比雪夫滤波电路进行变换和简化，设了计了集成8阶切比雪夫滤波器电路。该设计运用μA741运算放大器及开关电容时域宏模型，开关电容的时钟频率为128kHz。计算机模拟说明，其结果与理论计算值相符，可为其器件级设计提供分析依据。     

黏稠电介质的介电常数测量电容器的研制

研制了用于测量黏稠电介质的相对介电常数的实验装置。该装置通过交流电桥测量出空气电容与介质电容，进而可推算出介质的相对介电常数，对蓖麻油的测试表明，该装置方便，实用，有较高的精度。     

一种用单片机测量电容的新方法

根据一阶线性电路暂态分析理论，提出了一种新的智能化的电容测量方法．该方法采用单片机技术并设计了外部转换电路，无需交流供电及稳频稳压，与常用的电容测量方式相比，具有成本低、测量精度高、范围广和易操作等特点，有开发价值．     

KUSTERS轧光机缝头探测器的应用

德国ＫＵＳＴＥＲＳ公司制造的轧光机使用的缝头探测器，其探头采用电容厚度传感器，这种电容传感器结构简单，检测灵敏度高，抗干扰能力强，工作稳定可靠。     

差动输出式金属检测装置的研制

我厂于1975年就曾安装一台电子管电容三点式振荡金属检测装置,效果不显著,使用不到一个月,因电子管老化就不能使用。1978年又由清棉保全小组提出原棉内的金属物对清梳设备损坏严重,仅一年来的不完全统计,就给国家造成20万元的损失。原棉中的金属,必须设法除去,否则安全生产就得不到保障。随后,清棉保全同志又安装了一台晶体管电容三     

电容检测纱线传感器转换特性对纱线不匀率测试的影响

讨论了纱线测试中受电容检测纱线传感器转换特性的非线性影响，测得的条干不匀率值与纱线的实际条干不匀率值之间的差异，从理论上估计了纱线在不同的电容检测槽内测试时，由于其截面充满系数不同而引起的相对差异，并用试验数据加以验证。     

Alternate charging and discharging of capacitor to enhance the electron production of bioelectrochemical systems

A bioelectrochemical system (BES) can be operated in both "microbial fuel cell" (MFC) and "microbial electrolysis cell" (MEC) modes, in which power is delivered and invested respectively. To enhance the electric current production, a BES was operated in MFC mode first and a capacitor was used to collect power from the system. Then the charged capacitor discharged electrons to the system itself, switching into MEC mode. This alternate charging and discharging (ACD) mode helped the system produce 22-32% higher average current compared to an intermittent charging (IC) mode, in which the capacitor was first charged from an MFC and then discharged to a resistor, at 21.6 Ω external resistance, 3.3 F capacitance and 300 mV charging voltage. The effects of external resistance, capacitance and charging voltage on average current were studied. The average current reduced as the external resistance and charging voltage increased and was slightly affected by the capacitance. Acquisition of higher average current in the ACD mode was attributed to the shorter discharging time compared to the charging time, as well as a higher anode potential caused by discharging the capacitor. Results from circuit analysis and quantitatively calculation were consistent with the experimental observations.     

无功补偿自动投切装置的研究

介绍了电力系统中的电容器无功补偿问题。分析了装设不可调电容器组进行无功补偿存在的问题。说明了采用电容器组自动投切装置的重要意义。     

超级电容在电动汽车电池能量回馈中的应用

为了解决电动汽车制动时产生的巨大冲击电流对电池寿命的影响问题,搭建了仿真电动汽车电池测试平台,来研究超级电容对电动汽车电池能量回馈的作用效果.在VC6.0环境下开发了采集数据和控制负载的上位机软件,软件通过CAN总线与电池管理系统通信实现电池数据的采集,通过485总线与变频器通信实现负载的控制.基于上述平台,设计并完成了超级电容对电流冲击的吸收能力实验和超级电容对能量回收的影响实验.研究结果表明,超级电容能使电池从放电到充电有较长的缓冲时间,大大减少了对电池的伤害.此外,在有超级电容的情况下,电机启停周期内,可以节省较大的能量消耗,而且节省的能耗随着启停周期的减小而增加.     

Comparison of the energy performance of pulse generation circuits for PEF

Pulse shaped voltages are required for preservation of food with PEF. Several pulse forms generated by a variety of circuits are compared with respect to required energy. The analysis includes square pulses, trapezoidal pulses, exponential decay pulses and oscillatory and over-damped oscillatory pulses. The base of comparison is the establishment of a certain minimum voltage level during certain minimum time. The comparison concerns the dissipation in a resistive load, which is considered to be representative for a category of loads, including PEF. Furthermore, the ratio between initial capacitor voltage and corresponding threshold voltage is compared as this parameter reflects the required hold voltage of the switch in the circuit. The analysis shows that the efficiency approaches 100% for hard switched circuits and circuits with transmission lines. For highly damped RLC-circuits with capacitor C, inductor L and load resistance R the maximum obtainable efficiency is between 37 and 47% where the capacitor C has to be charged to 1.6–1.8 times the desired threshold voltage. For oscillating damped sinusoids the maximum efficiency is between 47 and 52%, however, the capacitor has to be charged to 1.8–3 times the threshold voltage. Graphs with an example are provided to determine circuit parameters from a certain pulse specification.     

应用无功补偿技术的注意事项

介绍自激、过电压和谐波对电容器组的影响及解决方法。     

FA304型并条机的电容式刹车装置

用电容器做为主要元件的刹车装置在新型高速并条机上得到广泛应用。本文就其工作原理及实际调节做了叙述，对防止齿轮反啮合的作用也做了介绍。     

Influence of pulsed electric field energy on the damage degree in alfalfa tissue

The objectives of this study were to investigate the influence of pulsed electric field (PEF) parameters on the damage degree of alfalfa mash, and to determine the relationship between the maximum damage degree and the energy used. Alfalfa mash was treated with PEF at various electric field strengths of 1.25, 1.90, and 2.50 kV/cm. The capacitance of the discharge capacitor was varied from 0.5 to 1.5 μF in steps of 0.5 μF. The pulse number was increased gradually to the point where the impedance became constant. There was no significant increase in the rate of damage beyond 0.5 kJ applied energy. The rate of change of the damage degree at 0.5 kJ was highest when the capacitance was 1.5 μF for all the voltages. Increase in the electric field strength led to decrease in energy needed to obtain the maximum damage degree. To achieve an efficient result for alfalfa juice extraction, the capacitance of the discharge capacitor should preferably be 1 μF or more. In order to minimize energy consumption for a given damage degree in alfalfa, it is desirable to have the highest energy per pulse and fewer number of pulses.     

基于弧形电容器的浆纱回潮率在线测量

为提高上浆质量以及解决使用接触式电阻含水率测量仪会破坏浆膜的问题,设计开发了基于弧形电容器的浆纱回潮率在线测量系统。根据浆纱在弧形电容器中的电场模型和电容法测量原理,利用指数回归算法建立电容差与回潮率的函数模型。上浆时,浆纱穿过弧形电容器,电感、电容、电阻(LCR)电桥测试仪将测量的电容值数据传到上位机,上位机根据模型计算出实时浆纱回潮率。讨论了弧形电容器结构、LCR电桥测试仪测试参数、环境温湿度、浆液含固率、浆纱线密度、回潮率对测量电容值的影响。实验结果表明：电容值受LCR电桥测试仪测试频率的影响较大;电容值随电容器结构参数极板长度、极板包角的增大而增大,与极板曲率半径呈负相关;环境温湿度会对电容值产生复杂影响,因此要求在恒温恒湿条件下进行测量;浆纱回潮率对电容值的影响显著,且回潮率与电容差呈指数函数关系。在上浆机上使用电容式回潮率在线检测系统进行测试,得到的浆纱回潮率与烘箱法测量结果相比平均误差小于5%,本文系统具有一定的工程实用价值。     

Measurement of Dielectric Properties for Moisture Determination of Dextrins

Dielectric properties of dextrins were investigated. The experiments performed enabled to determine the relationship between the moisture content of white and yellow dextrins, the capacitance of the measuring capacitor filled up with dextrins and the coefficient of dielectric losses tg ± measured for various frequencies of applied voltage. A measuring capacitor for quick measurement of moisture of powdered materials was constructed. To ensure constant density of material in the measuring region, an electromagnetic vibrator was employed. The sensor was used for moisture determination of white and yellow dextrins. The results obtained showed the linear relationship between the moisture content and the voltmeter readings. Based on this relations, a measuring system for moisture determination of dextrins was designed and built.