共查询到17条相似文献,搜索用时 265 毫秒
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为了分析接地网腐蚀后的性能,采用场路结合的算法,建立了一种接地网不等电位模型并进行仿真计算。利用节点电压方程和导体之间的互阻关系,形成ATP-EMTP仿真电路。通过对接地网导体腐蚀变细,电流注入点附近导体腐蚀断线和接地网边沿边角处导体腐蚀断线等情况下地表电位分布的仿真计算可以看出,接地网电流注入点附近及边沿边角处导体腐蚀断线会造成接地网内部巨大的电位差。研究表明,接地网应重点加强电流注入点附近及边缘边角处的抗腐蚀性能。 相似文献
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在接地网的计算模型中,一般是将接地网导体进行微元段的划分,然后求解每段导体注入土壤的泄漏电流,空间任意一点的电位都能够通过求解这些电流的"响应和"得到,从而计算接地网的电位分布、泄漏电流分布以及地表电位分布等。该文通过理论分析,建立了均匀土壤中的接地网不等电位计算模型,对接地网的地表电位分布进行计算。 相似文献
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在雷雨多发期 ,为了安全不间断播出 ,各台站应有安全可靠符合要求的防雷地线。地线分为工作地线和保护地线两种 ,接地电阻对不同设备有不同的要求 ,发送机房接地电阻应 <1Ω ,设备保护地线接地电阻应≤ 8Ω ,避雷地线接地电阻要≤ 10Ω。地线接地电阻的大小与土壤的导电性能、导体尺寸、接地体与土壤接触的松紧、埋设深度有关。土壤电阻系数见表 1。表 1 土壤电阻系数表土壤性质土壤电阻系数Ω/cm泥沼 2 5 0 0黑土 5 0 0 0粘土 60 0 0砂质粘土 80 0 0 根据导电材料的电阻率及本台实际情况 ,选用合适的材料做导体 (接地线、接地体 )。… 相似文献
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为了分析接地网电流注入点腐蚀后的性能,建立了一种接地网不等电位模型。利用节点电压方程和导体之间互阻抗的关系,形成ATP-EMTP仿真等效电路。通过对接地网电流注入点处导体腐蚀断线情况下地表电位分布的仿真计算,可以看出电流注入点附近的地电位升变得很高,而且斜率很大,增加了跨步电压的危险和多点接地设备受损的可能。研究表明,接地网应重点加强电流注入点附近的强度和抗腐蚀性能。 相似文献
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基于ATP-EMTP的接地网电流注入点腐蚀性能研究 总被引:1,自引:0,他引:1
为了分析接地网电流注入点腐蚀后的性能,建立了一种接地网不等电位模型.利用节点电压方程和导体之间互阻抗的关系,形成ATP-EMTP仿真等效电路.通过对接地网电流注入点处导体腐蚀断线情况下地表电位分布的仿真计算,可以看出电流注入点附近的地电位升变得很高,而且斜率很大,增加了跨步电压的危险和多点接地设备受损的可能.研究表明,接地网应重点加强电流注入点附近的强度和抗腐蚀性能. 相似文献
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An improved transmission-line model of grounding system 总被引:2,自引:0,他引:2
Yaqing Liu Zitnik M. Thottappillil R. 《Electromagnetic Compatibility, IEEE Transactions on》2001,43(3):348-355
This paper presents a time-domain transmission line model of grounding system, which includes the mutual electromagnetic coupling between the parts of the grounding structure and the influence of air-earth interface. The model can be used to simulate the transient behavior of the grounding system under lightning strike. The simulation results are in good agreement with that of the model based on the solution of full Maxwell's equations. The influence of different parameters, such as the soil relative permittivity ετ, the soil resistivity ρ, and the conductivity and diameter of the conductor, on the transient voltage distribution of the grounding system is investigated. It shows that, among the parameters investigated here, the soil resistivity is the most important parameter that affects the transient response of bare buried conductors. The soil permittivity has very little influence on the transient response of the grounding system when the grounding system is buried in the soil with low resistivity, but have moderate influence in the soil with extremely high resistivity. The conductivity of the conductor and skin effect have practically no influence on the peak transient voltage of the grounding system. Increase in conductor diameter tends to decrease the peak transient voltage. The model presented in this paper is simple, but sufficiently accurate and can be used easily in engineering practice. Since the model is in the time domain, it could be easily coupled to the other time-domain models of nonlinear surge-protection components 相似文献
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探讨了利用低频阻流圈、共用接地装置以及光缆传输方式解决因接地电位的不同而造成的视音频信号在传输过程中受到低频交流干扰的问题。 相似文献
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导线是飞机电源系统电能传输的主要载体。由于邻近效应,并排敷设相邻导线的电流有效值、频率等因素会影响导线阻抗值发生变化。为确定由于邻近效应引起的导线阻抗参数的变化,利用仿真软件Maxwell 2D/Simplorer建立并排敷设导线仿真模型,分析在邻近导线电流有效值、频率变化时,被测导线电阻、电感的变化规律,并对引起阻抗变化的原因进行了分析。结果表明:由于邻近效应和趋肤效应,被测导线的电阻值会随邻近导线电流频率和有效值的增大而增大;被测导线的电感值随邻近导线电流有效值的增大而增大,随邻近导线电流频率的增大而减小;在相同频率下,并排敷设时被测导线电阻、电感比单根敷设时大。 相似文献
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Pallem C. Chowdhuri P. Demko J.A. Gouge M.J. 《Applied Superconductivity, IEEE Transactions on》2006,16(1):31-37
The objective of this work was to determine the significant parameters of a 3-GW 200-kV dc superconducting cable system which influence the transient voltage distribution in the various parts of the cable. The cable system consists of four coaxial metallic cylinders. It was found that the dielectric constant and the electrical resistivity of the soil significantly affect the severity of the transient voltages; lower dielectric constant and higher resistivity of the soil will increase the magnitudes of the transient voltages by increasing the earth-return impedance. It was also found that the effect of the conductor internal impedances of the cable is insignificant. Shorting the coaxial cylinders of the cryogen flow and the cryostat will lessen the severity of the transient voltages. Grounding the second, third, and fourth cylinders at regular intervals with low-impedance grounding impedance will also improve the transient performance of the cable. More research is needed to evaluate these procedures. 相似文献
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防雷设计中的接地问题 总被引:3,自引:0,他引:3
针对防雷设计中电子设备的防雷接地,从外部防雷装置中接地体的选用、有效降低接地电阻的大小来符合国家标准要求以及选择合适的联合接地方式等3个方面阐述了合理接地的问题。通过对布线、屏蔽和接地方式,空间电磁场对通信线路的电磁感应影响情况和降阻剂对接地电阻的影响试验,总结出了能够保护电子设备的安全布线和接地方式。 相似文献
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有损土壤上的多导体传输线的时域分析 总被引:6,自引:2,他引:4
将多导体传输线(MTL)的土壤复数阻抗拓展为土壤运算阻抗,采用Pade展开法,提出了计及土壤影响的多导体传输线的时域模型,建立了该模型的时域有限差分(FDTD)算法。通过对计及土壤影响的架空单导体和双导体传输线的波过程计算,表明本文方法的正确性,并可以应用于超高压变电站高压母线和超高压输电线路的瞬态电磁干扰计算。 相似文献