ELF Earth Return Coupling Into Power Systems

With the advent of the U.S. Navy's proposed ELF Communications System (Sanguine System), which would use an earth-return circuit to excite the earth-ionosphere cavity, earth-return current coupling into power systems has become important. The theoretical basis for coupling into power distribution systems is developed. A comparison is made between measured and predicted values of the induced voltage. Techniques which are useful in eliminating the effects of the induced voltage are described. The effectiveness of these interference mitigation techniques is demonstrated by comparing measurements on actual systems. Finally, data on power system interference are developed for use in communication system design tradeoff studies.     

ELF Coupling to Spherical Models of Man and Animals

The induced fields, currents, and power absorbed by spherical models of humans or animals when exposed to extremely low frequency (ELF) electromagnetic fields are calculated. Spherical models can be expected to provide values of the right order of magnitude. The induced fields are a sum of the quasistatic solutions for a sphere irradiated by a uniform electric and magnetic field. Calculations are provided for ELF fields emanating from the proposed Navy's Sanguine antenna and extra high voltage (EHV)/ultra high voltage (UHV) transmission lines proposed by the utility industry. The question of biological hazards from exposure to fields of these systems is also considered.     

ELF Electric Field Coupling to Dielectric Spheroidal Models of Biological Objects

The extremely low frequency (ELF) electric field coupling to dielectric spheroidal models of biological objects is studied. Simple expressions are obtained to determine the internal electric field strength induced inside two nonspherical spheroids; a prolate dielectric spheroid and an oblate dielectric spheroid. Certain numerical results are graphically presented for various geometric shapes of the spheroid. The results show that, unlike the symmetric dielectric sphere, the relative position of the spheroid with respect to the orientation of the impressed electric field is an extremely important parameter which considerably affects the electric field coupling.     

Electromagnetic Coupling Between Parallel Lines on a Uniform Earth

Electromagnetic (EM) coupling between parallel lines on a uniform earth influences the results of induced polarization and electromagnetic surveys This paper presents a simplified analysis which allows a fast calculation of EM coupling in the time domain for the dipole-dipole and Schlumberger arrays. The simplified results are in good agreement with the results of other workers.     

垂直电流在双层大地中的感应地电位

从麦氏微分方程组出发，推导了双层大地数学模型下垂直电流在空间各 产生的磁矢是一势及感应地电位的计算公式，并对公式进行了讨论，给出了几种典型情况的计算结果及输电线短路状况下一些重要性质。／     

水平电流在双层大地中感应地电位的理论分析

从麦氏微分方程组出发，推导了双层大地模型下水平电流在空间各点产生的磁矢量势及感应地电位计算公式。对该感应地电位公式进行了讨论。     

Image Theory Results for the Mutual Impedance of Crossing Earth Return Circuits

Suitable engineering expressions for the mutual impedance of crossing earth return circuits are derived by employing finitely conducting earth image theory techniques. It is shown that the image theory and previously derived analytical results, which are rather complicated, are in excellent agreement.     

SLF/ELF垂直电偶极子在理想导电地-电离层中的场

在理想导电地面与电离层条件下,我们导出了SLF/ELF垂直电偶极子在球形地-电离层壳体中产生的电磁场的球谐级数表达式,并提出了一种加速收敛算法。利用此算法分别算出了电场分量随传播距离、高度及工作频率的变化,所得计算结果与Barrick方法所得结果基本吻合。由于地面和电离层没有吸收损耗,地面与电离层之间产生的场是＂驻波＂,在ELF频段,其频率变化规律能正确反映出＂舒曼＂谐振现象。     

Line Impedance Measuring Instrumentation Utilizing Current Probe Coupling

The theory and instrumentation designed to measure the loop impedence of a power line are discussed. The theory of the system is derived first, followed by a discussion of the instrumentation, and finally an evaluation of the system accuracy is given.     

水平电流在双层大地中感应地电位的数值分析

从麦氏微分方程组出发，推导出双层大地模型下水平电流产生的感应地电位的公式，并利用该公式对一些典型情况进行了计算，分析限计算结果，给出了水平电流产生的感应地电位的一些重要性质。     

Symmetric Temperature Compensation for Photoelectric Coupling Current Transducer

The temperature characteristic of sensor probe at high-voltage side is anslyzed by using a photoelectric coupling current transducer.The principle of symmetric temperature compensation and the main idea of software design are proposed.The method increases measuring precision and has fairly great practicability.     

感性脉冲电流注入装置的SPICE电路建模

为预测电子设备传导敏感度试验中脉冲电流注入在设备端口产生的干扰强度及波形,建立了感性电流注入装置的SPICE(Simulation Program with Integrated Circuit Emphasis)电路模型.在将装置电路模块化的基础上,应用传输矩阵计算的方法,从实验数据中提取出各模块的电路参数或方程表达式,并转换为SPICE模型,最后再将各模块组合为完整的装置模型.频域和时域的实验显示,模拟结果和测量结果一致性较好.建立的电路模型可用于设计和优化脉冲电流注入试验.     

Coupling Current and AC Loss in LHC Superconducting Quadrupoles

One of the issues for the operation of the LHC accelerator at CERN are the field errors generated by coupling currents in the superconducting cables of the main dipoles and quadrupoles, especially during the initial phase of the energy ramp from injection conditions. Coupling current effects have already been measured in the superconducting dipoles, and results are reported elsewhere. This paper reports similar measurements that we have recently performed on different types of LHC superconducting quadrupoles (arc quadrupole, dispersion suppressor and matching section quadrupoles) to quantify the above effects and compare them to the values specified from the beam tolerances. Loss and field errors due to ramping are mainly determined by the contact resistance between the strands of the magnets cables. In this paper the is calculated for several quadrupoles measured using both the measured energy loss and the magnetic field errors during ramping of magnets.     

轨道电路抗不平衡牵引回流干扰的方法研究

轨道电路在铁路信号系统中属于故障率较高的设备,而钢轨中不平衡牵引回流的存在会对轨道电路产生干扰,大大增加了轨道电路的故障率。该文针对不平衡牵引电流对轨道电路的干扰,从轨道电路抗干扰角度入手,研究轨道电路抗不平衡牵引回流干扰的方法,从而减小轨道电路的故障率,提高轨道电路的可靠性。     

九芯电缆EMP耦合的电流注入法实验

介绍了用于电流注入法实验的三同轴和三平行实验装置及实验方法。研究了皮电流波形对芯电压的影响、电缆始末端电阻变化对芯电压的影响以及芯电压随电缆长度的变化关系。提出了电缆末端电阻变化对芯电压幅度影响的等效电压源模型，该模型可以对外场试验的结果给予合理的解释。     

红外地平仪电机电流遥测数据波动现象研究

对某型号卫星红外地平仪用直流无刷电机在卫星测试过程中出现的电机电流遥测数据波动现象进行了研究。该红外地平仪选用的直流无刷电机具有低转速、小负载特性。通过对该型直流无刷电机的稳速驱动电路进行分析,根据电路锁相工作原理,阐明了电机电流遥测数据波动现象的成因。机理分析表明,直流无刷电机电流遥测数据波动现象是由于电机换相时产生的电流尖峰被采样电路采样到所致,不影响电机的安全可靠工作,也不影响产品在地面及在轨工作的使用寿命。通过对采样信号生成软件进行优化,可有效避免电机电流遥测数据波动现象。     

Ceramic electrodes for ELF bioeffects studies

Whenever metal electrodes are used for chronic exposure of biological material to ELF electric fields in a liquid medium, there is a possibility that observed effects are caused directly by ions from the electrodes rather than by the electric field. The problem can be avoided by using insulated electrodes, but ordinarily this severely limnits the fields which can be obtained in the medium. We show here that by using high dielectric constant ceramic electrodes, current densities greater than 10 A/M2 are achievable at frequencies above 50 Hz.     

Bandwidth Conversion of ELF Noise Parameters

The Field-Lewinstein-Modestino model represents ELF noise as the sum of Gaussian and impulsive components. This model has proven to be accurate and is especially convenient for analysis and simulation. However, the parameters of the model are bandwidth dependent and have been measured for only a few specific bandwidths. No method of calculating the parameters for other bandwidths has been presented. This paper derives such a method by equating the second and fourth moments of the impulsive component of the ELF noise at the input and output of the filter.