电磁式电流互感器的GIC谐波响应特征研究

发布时间：2018-06-06 08:15

本文选题：地磁感应电流 + 电磁式电流互感器　；参考：《华北电力大学》2014年硕士论文

【摘要】：电磁式电流互感器(CT)是目前广泛应用于电力系统中重要的电气二次设备,能否安全可靠地传变一次电流对电气计量及继电保护装置都具有重要的影响。地磁感应电流(GIC)和运行于单极-大地回路方式的高压直流输电系统(HVDC)会使电力系统中的电磁式电流互感器产生直流偏磁,导致铁心饱和、励磁电流畸变并产生大量谐波,可能引起系统中电气计量误差和继电保护装置误动,严重威胁电力系统的安全稳定运行。目前对磁暴侵害电力系统引起变压器直流偏磁的问题展开了一系列研究,而对电磁式电流互感器的直流偏磁及其谐波的研究还比较有限。因此,本文提出对电磁式电流互感器的GIC谐波响应特征的研究,对电力系统的安全稳定运行具有重要意义。本文分析了地磁感应电流作用下电流互感器直流偏磁的产生机理,研究了电流互感器GIC偏磁的等效电路及铁心磁化模型,采用了基于Jiles-Atherton原理的电流互感器的模型。其次,在PSCAD/EMTDC电磁暂态仿真软件中,建立了交流系统中GIC作用下的电流互感器的直流偏磁的等效模型,并仿真分析了GIC对CT稳态和暂态传变特性的影响。通过改变GIC的大小和频率、电流互感器自身线圈的变比等影响因素,研究了励磁电流畸变和各次谐波分布水平。最后,分析了电磁式电流互感器的偏磁饱和对计量和保护设备可能造成的影响,提出电流互感器谐波的抑制措施。
[Abstract]:Electromagnetic current transformer (CTT) is an important electrical secondary equipment widely used in power system at present. Whether the primary current can be transferred safely and reliably has an important influence on the electrical measurement and relay protection device. Geomagnetic inductive current (GIC) and HVDC (high voltage direct current transmission system) running in unipolar earth circuit mode can cause DC bias magnetic field of electromagnetic current transformer in power system, cause saturation of iron core, distortion of excitation current and produce a large number of harmonics. It may cause the error of electrical measurement and the maloperation of relay protection device in the system, which seriously threatens the safe and stable operation of the power system. At present, a series of researches have been carried out on the DC bias of transformer caused by magnetic storm, but the research on DC bias and its harmonics of electromagnetic current transformer is still limited. Therefore, the study of GIC harmonic response characteristics of electromagnetic current transformer is of great significance to the safe and stable operation of power system. The mechanism of DC bias of current transformer under the action of geomagnetic inductive current is analyzed in this paper. The equivalent circuit and core magnetization model of GIC bias current transformer are studied. The current transformer model based on Jiles-Atherton principle is adopted. Secondly, in the PSCAD / EMTDC electromagnetic transient simulation software, the equivalent model of DC bias of current transformer under GIC in AC system is established, and the influence of GIC on the steady state and transient transfer characteristics of CT is simulated and analyzed. By changing the size and frequency of the GIC and the variable ratio of the coil of the current transformer, the excitation current distortion and the distribution level of each harmonic wave are studied. Finally, the influence of bias saturation of electromagnetic current transformer on measurement and protection equipment is analyzed, and the harmonic suppression measures of current transformer are put forward.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM452

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