特高压直流输电系统对地电场观测的电磁干扰研究

发布时间：2018-12-06 12:35

【摘要】：我国处于地震活动多发区域，遍布各地的地震电磁监测台承担着预报和监测地震活动的重要任务。然而，随着越来越多的特高压输电线路建设和投运，已无法避免对线路周边地震电磁观测台站产生一定的电磁干扰。本文针对直流输电系统对地震台地电场观测的电磁干扰进行了较为深入的研究，分析了直流输电系统对地电场观测影响的干扰机理，提出了入地电流在复合3维土壤中电位分布模型，推导了该模型下电位的求解方法，并由此开发了直流输电线路对地电场观测干扰的校正系统。主要内容如下：（1）分析了地电场观测仪器的工作原理，并研究了直流输电系统干扰地电场观测的特点，认为直流输电线路合成场、离子流入地和接地极入地电流是干扰的影响因子。（2）基于Deutseh假设法，通过仿真计算和现场实测验证的方法，研究了合成场及离子流的横向衰减规律，认为离子流入地可能微弱影响地电场观测，并引起观测干扰幅值的不确定性，但对千米外的地电场观测来说，直流线路的存在不会引起干扰。（3）建立了接地极入地电流在复合3维土壤中的电位分布模型，，得到了由泰勒公式展开的无穷阶级数构成的多层土壤结构格林函数，根据复数镜像法，推导了接地极入地电流在复合3维土壤模型中任一点的电位计算公式。研究表明，直流输电线路入地电流为地电场观测干扰的决定性影响因子。（4）在±800kV锦屏-苏南特高压直流输电线路带电调试期间，由中国电力科学研究院（武汉）、三峡大学、中国地震局地震研究所组织，通过换流站、地震台站和野外布点联合观测的方式，分别开展了特高压直流线路、接地极对地电场观测干扰实验。对比分析仿真计算结果和实验数据，发现干扰计算模型最大误差不超过15%，并由此开发了“直流输电线路对地电场观测干扰校正系统”。
[Abstract]:Our country is in the area of frequent seismicity, and the seismic electromagnetic monitoring stations all over the place undertake the important task of predicting and monitoring seismic activity. However, with more and more UHV transmission lines being constructed and put into operation, it is impossible to avoid some electromagnetic interference to the seismic electromagnetic observation stations around the lines. In this paper, the electromagnetic interference (EMI) caused by DC transmission system to geoelectric field observation is studied deeply, and the interference mechanism of HVDC system on geoelectric field observation is analyzed. In this paper, a potential distribution model of earth current in composite 3D soil is proposed, and the solution method of potential under this model is derived, and a correction system for the interference of DC transmission line to earth electric field observation is developed. The main contents are as follows: (1) the working principle of the geoelectric field observation instrument is analyzed, and the characteristics of the interference geoelectric field observation of HVDC transmission system are studied, and the composite field of HVDC transmission line is considered. The ion flow into the ground and the earth current at the earth pole are the influencing factors of the interference. (2) based on Deutseh hypothesis, the transverse attenuation law of synthetic field and ion current is studied by simulation and field measurement. It is considered that ion flow may have a weak effect on the observation of geoelectric field. It also causes uncertainty of the amplitude of the observed interference, but for geoelectric field observation over a kilometer away, the existence of DC line will not cause interference. (3) the potential distribution model of earth current in complex 3D soil is established, and the Green's function of multi-layer soil structure, which is composed of infinite class number of Taylor's formula, is obtained, according to complex image method. The formula for calculating the potential of the earth current at any point in the composite 3D soil model is derived. The results show that the earth current of DC transmission line is the decisive factor of the earth electric field observation interference. (4) during the commissioning of 卤800kV Jinping-Sunan UHVDC transmission line, it was organized by the China Institute of Electric Power Sciences (Wuhan), the three Gorges University, and the Seismological Research Institute of the China Seismological Bureau. The interference experiments of UHV DC line and earth pole to earth electric field observation were carried out in the way of joint observation of seismic stations and field distribution points. By comparing the simulation results with the experimental data, it is found that the maximum error of the interference calculation model does not exceed 15%, and a "interference correction system for DC transmission line to earth electric field observation" is developed.
【学位授予单位】：三峡大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM721.1

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