矿热炉是通过炉内三相电极产生电弧热与电阻热对炉料进行加热，使炉料产生氧化还原反应来冶炼铁合金。目前大部分冶炼企业都采用一次侧电流人工调节矿热炉三相电极升降，这种方法不能有效实现三相熔池功率平衡，而采用基于变压器二次侧大电流作为控制参数的恒阻抗控制策略，能较好地实现三相熔池功率平衡。但二次侧电流高达数万安培，检测非常困难，通过理想变压器变比方式计算得到二次侧电流误差非常大，针对这些问题，本文采用罗氏线圈进行二次侧电流检测，主要做了如下研究：（1）综述矿热炉电极升降国内外现状及大电流检测现状，研究矿热炉生产设备和工艺流程，为之后的矿热炉电极升降自动控制系统设计奠定基础。（2）针对矿热炉变压器二次侧电流难以检测的问题，设计罗氏线圈检测系统，研究罗氏线圈检测二次侧大电流的方法，罗氏线圈输出的电压信号经积分放大后利用快速傅里叶变换（FFT）分解出各次谐波，并对各次谐波分别进行矢量求和，完成矿热炉变压器二次侧电流的检测，通过MATLAB仿真和现场测试，证明该方法有效、可行。（3）针对矿热炉生产工艺，利用变压器二次侧电流，设计电极升降自动控制系统总体方案，并进行系统软硬件设计。硬件上采用工控机和西门子S7-200PLC相结合的上下位结构，软件上以Visual Basic 6.0为开发平台并结合Access数据库，编制矿热炉电极升降自动控制系统软件，实现电极升降的恒阻抗控制策略。（4）整套控制系统在现场进行调试和试验，完成数据采集和对电极的自动控制，达到矿热炉电极升降自动控制系统的要求。基于大电流检测的矿热炉电极升降自动控制系统的实现，对于冶炼企业降低能耗、减少人工劳动强度和提高矿热炉自动化水平具有十分重要的意义。

Submerged arc furnace heats the burden through the arc heat and resistance heat generated by the three-phase electrode in the furnace to make the burden generate redox reaction and then smelt ferroalloy. At present, in the most of domestic metallurgical plants, the primary side current by manual adjustment is used to control the three-phase electrodes lifting. This method cannot effectively realize the power balance of the three-phase molten pool. However, using the constant impedance control strategy of taking in view of the large current on secondary side of the transformer as the control parameter can better realize the power balance of the three-phase molten pool. But the secondary side current reaches several tens of thousands of ampere. It is quite difficult to detect. The error of using ratio of traditional transformer to calculate secondary side current is very large. For these problems, the Rogowski Coil is used to detect the secondary current in this thesis, the key contents are shown below:(1) The domestic and foreign situation of submerged arc furnace electrode lifting and large current detection are reviewed. It studies the production equipment and technological process of submerged arc furnace, and lays a foundation for the design of electrode lifting automatic control system. (2) Aiming at the problem that the secondary current of the submerged arc furnace transformer is difficult to be detected, this paper designs Rogowski Coil detection system and studies the method of detecting the secondary current by Rogowski Coil. After integration and amplification of the voltage signal outputted by Rogowski Coil use Fast Fourier Transform to decompose each harmonic wave, and sum for each harmonic wave to complete the detection of the secondary current of the submerged arc furnace transformer. Through MATLAB simulation and field test, the feasibility and effectiveness of the method are proved.(3) According to the production process of submerged arc furnace, the overall plan and hardware and software of automatic control system for submerged arc furnace electrode lifting are designed which use transformer secondary side current. The upper and lower structure of combining industrial control computer and Siemens S7-200PLC is chosen in the hardware part. Visual Basic 6.0 is used as the development platform with Access data base to write software program of automatic control system in the software part. The constant impedance control strategy of electrode lifting is realized.(4) The whole control system is debugged and tested in the field, the data acquisition and automatic control of the electrode are accomplished. The debugging results reach the requirements of the control system. Realization of automatic control system for submerged arc furnace electrode lifting based on the large current detection has important significance for the smelting enterprises to reduce the energy consumption and labor intensity, and improve the automation level of the submerged arc furnace.