Research of Metering Standard Device in Industry of Heavy Direct Current
|School||Huazhong University of Science and Technology|
|Course||Electrical detection technologies|
|Keywords||Magnetic modulator Current Comparator Multi-channel Open- Proportional error|
DC current electrolysis industry has a wide range of applications, with the strong development of UHV DC transmission, the DC current in the field of power systems will be broadened. However, the measurement work is lagging behind, leading to a lot of wasted energy, which does not comply with the requirements of energy conservation and the development of low-carbon economy. It is necessary to establish a direct current measurement standards, the development of the relevant standard metering device, a prominent role in the cause of energy conservation in order to truly reflect the measurement technology. The subject of this study is the national quality inspection nonprofit industry research and special projects - DC current measurement standard device (No. 200710107). This study is an industrial device with DC current measurement standards, its role is not only the site online monitoring of DC current, and relatively easy to to check industrial field use DC transformer, in order to ensure the accuracy and reliability of the measurement work. The paper first introduces the status quo of the DC current measurement work to clear the significance of the study of this subject. Chapter 2 introduces the dual-core differential structure suitable for on-site detection of small DC magnetic modulator mechanism. And dual-core magnetic modulation DC comparator principle of the measurement of large currents. This paper uses a the magnetic modulation opening multi-channel DC comparator in order to solve a variety of practical problems in the industrial field. Chapter 3 describes the hardware part of the design work, including the sensor head, the signal processing circuit and a digital display part of the design. Wherein the signal processing circuit includes a band-pass filter, phase-sensitive demodulation, DC amplification and power amplification circuitry. Chapter 4 analyzes the proportion of error of the measuring standard device, as well as the actual test. First introduced the concept of the current transfer coefficient proved strictly proportional error is actually the relative error of the current transfer coefficient. Detailed analysis based on the principle of the error of the measurement scale of the voltage difference method and the current docking method, and to obtain a final calculation expression. The the last analog field test results confirmed the standard metering device error ratio less than two millionths. Chapter 5 analyzed from a theoretical point of opening multi-channel comparator antimagnetic characteristics a stable working mechanism of the air-gap characteristics of the comparator. The paper concludes the work of the full text and proposed areas for further research work.