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Study on Electromagnetic Environment around Electric Power Facitities

电力设施周围电磁环境研究

基本信息

批准号：
07405013
负责人：
HIKITA Masayuki
金额：
$ 10.18万
依托单位：
Kyushu Institute of Technology (1996)Nagoya University (1995)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07405013/
关键词：
transmission line reduced model of tower magnetic field distribution partial discharge electromagnetic wave phase gate control diagnostic technique 電磁環境電力施設周辺極低周波磁界アモルファス磁性体センサ

项目摘要

Magnetic field around power transmission line exhibits complicated characteristics. It is 3-dimensional distribution and affected by three-phase current and various condition of current, such as unbalanced current and superimposed harmonics. Magnetic field distribution may be distorted by transmission towers. However the influence of these parameters on the generated magnetic field has not been clarified.In this study, we investigated the low frequency (60Hz) magnetic fielddistribution using 1/40 reduced-scale power transmission line and tower model. We made clear the effect conductor sag and towers on the magnetic field distribution by comparing calculated and measured field.In order to make clear the magnetic field behavior around power transmission line and the tower, we measured the magnetic field distribution using 1/40 reduced-scale transmission line and tower model.This model enables us to analyze the precise 3-dimentional profile of magnetic field as well as the effect of the c … More onductor sag and the tower. As a result, we found that the magnetic field component parallel to the line emerges around the tower and a main factor influencing the characteristics was the conductor sag. We could also obtain the perpendicular distribution of magnetic field around the transmission tower.Partial discharge (PD) may take place due to residual defects like metallic particles or microprotrusions inside SF_6 gas insulated power apparatus such as GIS,leading to the failure breakdown. Thus, PD measurements are very effective and promising technique to diagnose GIS under operating conditions. However, the signal of PD occuring in SF_6 gas is very weak and susceptible to external noises which mainly consist of PD in air. Thus, it is important to distinguish the PD in SF_6 gas more sensitively from the external noises.From the above points of view, we have been investigating characteristics of electromagnetic wave spectrum radiated from PD in SF_6 gas and in air using wide-band antennas. In this study, we propose "phase gate control method" in order to reveal the dependence of the polarity of ac voltage on the electromagnetic wave spectrum. Using the phase gate control method, an attempt is made to separate electromagnetic spectrum caused by PD occurring in SF_6 gas from that in air. We also investigate the frequency range where PD spectrum in SF_6 gas alone can be detected under noisy conditions. On the basis of these results, we discuss the minimum detectable PD charge in SF_6 gas as a function of measuting frequency. Less

输电线路周围的磁场呈现出复杂的特点。它是三维分布的，受三相电流和各种电流状态的影响，如不平衡电流、叠加谐波等。输电铁塔可能会使磁场分布发生扭曲。然而，这些参数对产生的磁场的影响还不是很清楚。在本研究中，我们使用1/40缩尺输电线路和杆塔模型来研究低频(60 Hz)磁场分布。为了弄清输电线路和杆塔周围的磁场行为，采用1/40缩尺输电线路和杆塔模型测量了输电线路和杆塔周围的磁场分布。该模型使我们能够分析精确的三维磁场分布以及c…的影响更多的传导器凹陷和塔。结果发现，在铁塔周围出现了平行于导线的磁场分量，影响其特性的一个主要因素是导线凹陷。还可以得到输电杆塔周围磁场的垂直分布。由于SF_6气体绝缘电力设备(如GIS)内部的金属颗粒或微凸起等残留缺陷导致故障击穿，可能会发生局部放电。因此，局部放电测量是一种非常有效和有前景的运行状态下诊断地理信息系统的技术。然而，SF_6气体中的局部放电信号很弱，对外界噪声很敏感，而外界噪声主要是空气中的局部放电。因此，更灵敏地区分SF6气体中的局部放电和外界噪声是非常重要的。从以上角度出发，我们一直在使用宽带天线研究SF_6气体中局部放电和空气中局部放电辐射的电磁波谱特性。在这项研究中，我们提出了“相位门控制方法”，以揭示交流电压的极性对电磁波频谱的依赖关系。利用相位门控制方法，尝试将SF_6气体中局部放电产生的电磁频谱与空气中的局部放电产生的电磁频谱分开。我们还研究了在噪声条件下，仅在SF_6气体中可以检测到PD光谱的频率范围。在此基础上，讨论了SF_6气体中最小可检测Pd电荷量与测量频率的关系。较少