Quench Detection And Protection For HTS Transformer

HTS transformer has remarkable advantages of small size, light weight, stable performance, No pollution and so on. However, under the conditions of high current power system, quench of superconducting transformer which is a more serious problem, will endanger the safety of equipment and system directly, so it’s necessary to provide detection and protection against high-temperature superconducting transformer operation, also the research and development has important theoretical and practical significance.The paper describes the basic characteristics of high-temperature superconductors, the current research in domestic and foreign and the economic sense of HTS superconducting transformer in operation. By analyzing the experimental results about the Bi-2223/Ag HTS tapes’quench characteristics and the development processes after quench while the high current in different peak current, we found that the critical current of HTS tapes decreases with the increase of magnetic field. Meanwhile, the electromagnetic properties of high-temperature superconducting tapes Bi2223 were analyzed, providing theoretical guidance for the optimized design of high-temperature superconducting transformer. Next, a theoretical study on the no-load closing of transformer and the transient process caused by internal sudden short circuit fault is given. Using Matlab/Simulink simulations were carried out to its providing a theoretical basis for the quench protection strategies HTS transformer. Analysis of the superconducting transformer quench detection mechanisms and quench detection principle demonstrated by experimental analysis quench phase change quench detection principle. Meanwhile, the study of the quench detection method based on correlation function.Based on the analysis above, After carefully studied zero-dimensional quench analysis of ideal superconducting magnets, we got that superconducting magnets are usually super start from a certain point spread in a certain speed, the initial quench point is the magnets’ hot spots, the temperature named as Tmax should be a maximum value, which is limited by a certain value to limit the thermal stress and avoid material damage. The essence of quench protection is to protect the superconducting transformer’s superconducting coils. In the comparative analysis of several kinds of several superconducting coil quench protection circuit, We knew the quench protection is try to minimize the hot temperatures and the terminal voltage, and all the energy can be consumed in the coil itself after quench, in order to protect the superconducting transformer provides a theoretical basis.