ZGTD-C调容式自动跟踪消弧线圈

1基本原理 　　根据系统最大运行方式或今后电网发展情况及相应的电压等级来确定消弧线圈的额定容量(以过补为原则),即可确定消弧线圈在接地情况下提供的电感电流.再利用消弧线圈的特点增加二次电容负荷线圈,根据变压器阻抗变换原理,通过消弧线圈二次侧并接的若干组真空开关(或晶闸管)通断的组合来调节二次电容的容抗值,由折算到一次侧的容抗产生可调的容性电流,由于该容性电流与消弧线圈电感电流相位相反,呈相减关系.尽管消弧线圈电感电流不变和系统电容电流暂时不变,通过调节消弧线圈二次容抗的大小可方便地控制接地点的接地电流大小,即残流大小,以达到消弧抑制过电压的目的. 　　……     

基于磁通可控原理的新型消弧线圈系统

本文提出一种基于磁通可控原理的新型消弧线圈系统,当在消弧线圈的二次侧采用有源的方式注入一个与一次侧电流频率相同,相位相反,幅值连续变化的电流时,消弧线圈的一次侧电抗值可实现连续无级可调。该消弧线圈二次侧采用了多支路并联结构,以满足二次侧低压大电流的要求,且与二次侧只有一条支路的情况等效。当系统采用单极倍频的PWM斩波方式来跟踪一次侧电流来产生二次侧电流时,只要保持给定相同,二次侧各支路的输出完全相同。仿真结果证明了此新型消弧线圈系统的正确性。     

基于信号注入法的可控硅投切电容式消弧线圈

提出了基于信号注入法的可控硅投切电容式消弧线圈设计方案。彩从消弧线圈的副边向电网注入变频电流信号，测量系统电容电流，利用可控硅投切电容实现自动调谐的方法。实际现场运行表明，该型消弧线圈具有调节速度快，补偿精度高，无谐波危害，且无机械动作可靠性高等特点。     

查表式可控硅投切电容消弧线圈的研制

基于可控硅投切电容补偿的概念 ,提出了一种新型消弧线圈补偿装置 ,即查表式可控硅投切电容式自动消弧线圈 ,其工作原理为预先将补偿电流制成表格写入内存 ,在发生故障时很快切换到谐振状态附近。介绍了整个装置的设计方法 ,包括消弧线圈的参数计算和控制电路的结构设计。理论分析及 6kV系统实践表明 ,这种新型消弧线圈调节范围宽 (2 5～ 5 0A)、响应速度快 (<5个周波 )、伏安特性线性度好 ,无谐波干扰等。     

基于注入信号的消弧线圈电容检测方法

为利于消弧线圈自动调谐,提出了一种电力系统电容电流检测方法,即向消弧线圈二次侧线圈注入变频小电流,寻找系统对地电容与消弧线圈励磁电抗的谐振频率,可直接计算出系统对地电容值。此法用于磁通补偿消弧线圈时,不增加系统硬件成本,并可直接得到调节消弧线圈电抗值所需的重要参数—电流补偿系数α。     

微机人工二次谐波发电机定子单相接地保护

本文提出在发电机中性点消弧线圈（或配电变压器）的二次线圈中加入人工二次谐波电流，通过检测二次谐波电压与二次谐波电流间相位差，与基波零序电压保护一起可构成１００％定子单相接地保护     

一种基于极值法与相位法的新型消弧线圈研究

分析了消弧线圈的各种调谐原理,提出了采用极值法与相位法相结合的消弧线圈调谐来实现快速调谐.根据三相五柱式消弧线圈的工作原理,提出调节多组可控硅导通角获得补偿电感电流的控制方法,也提出了准确判断系统电容电流变化的判据以及在母联断开和闭合时采用CAN总线进行双机互联实现准确调谐的手段.     

洛阳热电厂10 kV系统消弧线圈补偿问题的研究

文章针对洛阳热电厂10 kV系统电容电流过大、中性点经消弧线圈接地易引起谐振,自动跟踪补偿装置造价又太高的问题,提出了保留原有消弧线圈和中性点阻尼电阻,在现有结线方式下增加一套能与原消弧线圈配合的自动跟踪补偿消弧线圈,以抵消用户无规则的电容电流变化,既限制了弧光接地过电压、减少原消弧线圈操作次数,又节省了资金.实际运行证明效果良好.     

基于滤波箱自适应扫频法的容性电流测试研究

消弧线圈动作通常会引起中压配网供电电压异常波动,准确的容性电流测试时实现精确补偿的前提。基于在电压互感器二次侧注入变频电流信号测试法,消除了对消弧线圈电感值的试探性调整环节,无需测量其它任何参数,将测量回路从高压侧转移至低压侧,实现了测量的安全与方便。此方法适用于任何类型的消弧线圈,测量过程可在系统正常运行时进行,该过程无需启动消弧线圈调协机制,有利于调谐装置的正常运行。     

消弧线圈响应时间的探讨

谐振接地系统中,消弧线圈的响应时间对快速熄灭电弧,保障人身和设备安全有着重要的意义,而少数厂家的误导对用户产生了错误的影响。为此通过对影响消弧线圈响应时间的各种因素进行详细分析,指出响应时间受系统参数影响,且与接地随机参数有关,主要取决于暂态励磁电流的衰减速度快慢。同时澄清了现有一些对响应时间的错误观点,并对目前应用最为广泛的调匝式和高短路阻抗变压器式(简称高阻抗式)两种形式消弧线圈分别提出了如何提高响应时间的措施。对于调匝式消弧线圈可以采用延时短接阻尼电阻的方式提高系统的阻尼率,加快暂态电流的衰减;对于高阻抗式可以采用可控硅不对称控制方式调节输出电流,提高响应时间。     

Adaptation of Discrete‐Type Cores for Secondary Coils of Wireless Power Transfer System for Railway

This paper examines the shapes of cores for secondary coils of the wireless power transfer (WPT) system for a railway. An infinitely long cable‐type coil is utilized as the primary coil for the WPT system because it is economical. Thus, this paper examines the ferrite core shapes for the secondary coils that are suitable for an infinitely long primary coil. The cores should be as thin as possible to reduce weight. However, bonding small cores to manufacture larger thin cores reduces the performance of the secondary coils. As a result, the cores are paradoxically required to be thicker. Therefore, this paper proposes the adaptation of thicker discrete‐type cores with the same volume as conventional flat‐type cores for the secondary coils.     

Circuit Analysis and Characterization of Contactless Power Transfer System with Variable Impedance

A contactless power transfer system using a repeater coil (repeater Coil topology) has been proposed as a method of suppressing overcurrent without power control during misalignment or no‐load. By installing a repeater coil between the primary and secondary coils, it is possible to increase the input impedance in the case of misalignment of the secondary coil or no‐load condition. In addition, another contactless power transfer system using primary parallel and secondary series resonance capacitors (PS capacitor topology) has been proposed. In the PS capacitor topology, the input impedance can be increased during misalignment of the secondary coil or no‐load condition similar to the repeater coil topology. In this paper, we evaluated the characteristics of both these topologies. First, we conducted a circuit analysis of the repeater coil topology and proposed a design method. In addition, we theoretically clarified the characteristic difference of the two topologies and experimentally evaluated the characteristics.     

基于一发多收线圈阵列的频域电磁法未爆弹探测技术

为了实现未爆弹目标的高效探测及定位,开发了一种小回线激励-阵列式线圈接收的主动电磁探测系统。采用偏心结构的收发线圈配置,实现了一次场的对消。通过接收线圈阵列排布,有效地提高了系统探测效率。提出了一种基于阵列线圈响应差分比较的未爆弹目标水平位置定位方法,并实验验证了可行性。研究结果表明,探测系统对于典型环状金属柱体的探测深度达到1 m,定位方法的计算值与真值误差在3.76 cm,实现了对未爆弹目标的准确探测和定位。     

电动汽车无线充电系统磁耦合线圈耦合系数的研究

针对电动汽车无线充电系统磁耦合线圈之间耦合系数小、存在偏移的问题,对磁耦合线圈的耦合系数进行了研究分析。首先根据无线充电系统串-串补偿模型,分析了耦合系数与传输功率和传输效率之间的关系。其次,比较了不同形状的线圈在相同围绕面积的条件下,耦合系数随线圈间气隙距离和偏移的变化。以圆形-圆形线圈为例分析了线圈内部参数变化对耦合系数的影响。最后,对比分析了圆形线圈增加磁芯时对耦合系数的影响。研究结果证明了所提方法的有效性。     

Overcoming high-field RF problems with non-magnetic Cartesian feedback transceivers

In extending human MR to field strengths approaching 10 T, the wavelength of electromagnetic radiation at the proton Larmor frequency becomes less than human body size and conventional radio-frequency coil circumference. Consequently, radio-frequency magnetic fields are better generated by an array of small coils than by one large coil. In this article, the primary problem of array coil interactions during transmission is examined, and a standard proposed whereby secondary induced currents should be less than 1% of the primary coil current. The use of cancellation methods and of power amplifiers with high output impedance to reduce interactions is examined in the light of this standard and found wanting. Non-magnetic Cartesian feedback transceivers functioning at the magnet entrance are then proposed as a solution that both reduces instrumentation cost and increases the bandwidth over which the standard may be met. The compromises inherent in instrument design are detailed and examples given of the innovative circuitry used. It is shown experimentally that when connected to interacting coils, two Cartesian feedback instruments function stably in accord with theory and such that the proposed standard is typically attained over a bandwidth of 22 kHz during transmission (much greater during signal reception)—enough for all current MR protocols.     

带有大中继线圈的无线充电磁耦合器抗偏移特性研究

感应式电能传输技术在电动汽车实际应用中不可避免地出现原副边线圈相对位置错位,这会导致系统效率下降、线圈过流等一系列问题。针对这些问题,提出一种带大中继线圈的三线圈磁耦合器结构用于提升系统抗偏移能力。结合解析法和有限元法,分析了影响系统效率的关键因素,研究了不同补偿参数下三线圈磁耦合器传输性能以及不同偏移程度下两线圈和三线圈的互感和损耗的变化规律,并验证了含大中继线圈的三线圈磁耦合器在提升抗偏移能力方面的独特优势。在此基础上,提出基于两线圈和三线圈切换的具有强抗偏移能力的磁耦合器优化设计方法。设计并研制了线圈尺寸为400 mm×400 mm的磁耦合器样机,实验结果表明在偏移尺寸达到线圈尺寸50%、输出功率为3 kW的情况下,磁耦合器效率可达95 %,相比传统两线圈磁耦合器效率提升5 %。     

Transmission analysis of electromagnetic induction RFID system

The transmission characteristics of the electromagnetic induction RFID systems are greatly influenced by the distance between the primary and secondary antenna coils and by the materials used in their design. In this paper the induced current of the secondary antenna coil is calculated by the 3D finite element method when both the primary and secondary antenna coils are operated in resonant circuits. The influences of the analyzed parameters on the transmission characteristics are demonstrated. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 173(4): 38–45, 2010; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21019     

运动设备无接触供电系统耦合特性的研究

本文采用磁通方法和诺伊曼公式研究了不同形状线圈自感以及线圈间发生位移时互感的计算,进一步分析研究了初、次级线圈的形状和尺寸对耦合变化特性的影响,最后通过实验研究,验证了分析所得结果.实验和计算结果均表明,运动设备无接触供电系统采用矩形线圈对于稳定耦合性能更为有效,稳定性主要由线圈宽度和初、次级长度比决定.线圈越窄,初、次级长度比越大,稳定性越好.     

电力变压器螺旋线圈磁场分析研究

以240 MVA大型电力变压器低压螺旋绕组的实际结构尺寸为例,针对大型电力变压器螺旋线圈引起的扭转变形问题,采用数值积分的方法对变压器实际螺旋线圈中的轴向电流分量对漏磁场及扭转变形的影响进行了分析,给出了螺旋线圈在考虑轴向电流分量时辐向磁场沿线圈高度的分布规律.     

Improvement of equivalent magnetic coupling coefficient of wireless power transfer system with multiwinding transmission coil

This article proposes a novel method of improving the overall coupling coefficient of a wireless power transfer system by using a four‐winding transformer of which two pairs of windings each are connected in parallel in the primary side and secondary side. By weakening the coupling coefficients k_c between the parallel windings, the overall magnetic coupling between the primary side and secondary side of the transformer is improved. In order to confirm the validity of the proposed method, a conventional high‐k_c four‐winding transmission coil and the proposed low‐k_c four‐winding transmission coil are experimentally assessed. Then, the coils are introduced into a nonresonant inductive power transfer system utilizing a dual active bridge converter in order to confirm the correction of the input power factor. As a result, the overall magnetic coupling of the proposed four‐winding coils was found to be improved by 17% compared with the overall magnetic coupling of the conventional coil. Moreover, the input power factor for the entire load is corrected with the proposed four‐winding coil. Therefore, a low k_c is effective in improving the overall magnetic coupling.