直流小电流互感器的研究与设计

发布时间：2018-03-13 20:10

本文选题：直流漏电流　切入点：磁感应互感器　出处：《华北电力大学》2017年硕士论文　论文类型：学位论文

【摘要】：电力系统中直流供电系统是一个复杂且纵深程度高的系统,测量直流漏电流对于保障电力系统正常运行具有重大意义。磁调制互感器在电力系统中被广泛用于测量直流漏电流,然而传统的磁调制互感器算法在测量直流漏电流时并不十分适用。目前针对直流漏电流的测量算法研究较少,且针对温度对于互感器的影响研究较少。本文针对传统磁调制互感器算法进行改进,使其适用于测量直流漏电流,并且设计出一款使用改进算法的互感器系统。针对磁芯进行了ANSYS温度场建模,更好的了解温度对互感器的影响,并且针对这种影响提出了补偿方法。本课题的开展,能够弥补现有研究的不足,提高现有的直流漏电流测量水平。本文对国内外与本课题相关的研究成果进行分析,对现有的测量直流漏电流的方法进行总结,对测量直流漏电流与现有的相关研究成果进行深入研究,提出合理的测量方法,设计出基于FPGA的直流小电流互感器。互感器分为硬件设计和软件设计两个方面。硬件设计为软件设计提供了平台,针对直流漏电流采用差分算法,并且采用双线圈进行测量,更好的提高了精度。而且由于FPGA所拥有的大量的IO资源,为日后的多路互感器的扩展提供了可能。软件部分使用了FPGA的内核开发,拥有串口输出和DA电压输出两种输出方式,使得互感器的输出更加直观。通过实验数据证明本文所设计的互感器测量精度满足电网中对于检测的要求。最后为解决磁芯受温度影响的问题,本文针对磁芯的温度场建立了ANSYS模型,在同等条件下观察温度与磁芯磁导率的关系。在确定了温度与磁芯磁导率的关系之后,针对当前时刻待测电流的不同,观察不同的待测电流与磁芯磁导率的关系,针对这两种对磁芯磁导率的影响源提出相对应的补偿策略。
[Abstract]:DC power supply system in power system is a complex and high depth system. It is very important to measure DC leakage current to ensure the normal operation of power system. Magnetic modulation transformer is widely used to measure DC leakage current in power system. However, the traditional magnetic modulation transformer algorithm is not very suitable for measuring DC leakage current. There is little research on the effect of temperature on transformer. In this paper, the traditional magnetic modulation transformer algorithm is improved to make it suitable for measuring DC leakage current. And designed a transformer system using the improved algorithm. The ANSYS temperature field modeling for the core, a better understanding of the impact of temperature on the transformer, and proposed a compensation method for this impact. It can make up for the deficiency of the existing research and improve the current level of DC leakage current measurement. This paper analyzes the research results related to this topic at home and abroad, and summarizes the existing methods of measuring DC leakage current. The measurement of DC leakage current and existing related research results are deeply studied, and a reasonable measurement method is put forward. A DC small current transformer based on FPGA is designed. The transformer is divided into two aspects: hardware design and software design. Hardware design provides a platform for software design. Because the FPGA has a lot of IO resources, it is possible to expand the multiplex transformer in the future. The software part uses the kernel of FPGA, and has two output modes: serial port output and DA voltage output. Through the experimental data, it is proved that the measuring accuracy of the transformer designed in this paper meets the requirements of the detection in the power network. Finally, in order to solve the problem that the core is affected by the temperature, the output of the transformer is more intuitionistic. In this paper, the ANSYS model is established for the temperature field of magnetic core, and the relationship between temperature and permeability is observed under the same conditions. After determining the relationship between temperature and permeability of magnetic core, the difference of current to be measured at present is discussed. The relationship between different measured current and magnetic core permeability is observed, and the corresponding compensation strategies are put forward for the two kinds of influence sources of magnetic core permeability.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM45

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