Sheet Metal Forming processes are those in which force is applied to a piece of sheet metal to modify its geometry rather than remove any material. The applied force stresses the metal beyond its yield strength, causing the material to plastically deform, but not to fail. By doing so, the sheet can be bent or stretched into a variety of complex shapes. Sheet Metal Forming Sheet Metal Forming,Metal Forming,Metal Forming Machine,Sheet Metal Forming Machine Chongqing Jin Te Rui Machine Co.,Ltd , http://www.jtrmachining.com
Research progress on key technologies for preparation of high temperature superconducting current limiters in plasma
[ China Instrument Network Instrument Development ] On January 18th, the Plasma Institute's General Research Office cooperated with China Electric Power Research Institute Co., Ltd., State Grid Liaoning Electric Power Company Electric Power Research Institute and Tsinghua University to independently prepare self-trigger magnetic bias. The superconducting unit-parallel strip type YBCO superconducting non-inductive coil in the superconducting current limiter was tested by 50A critical current performance. The test results show that the critical current of the superconducting coil is 81A in the environment of liquid nitrogen immersion, exceeding the target requirement of 50A. The 150A fault current surge lasts for more than 3s, and has better quenching stability. As the operating temperature decreases, the critical current has room for further improvement.
The superconducting current limiter utilizes the quenching characteristic of the superconducting material to generate a nonlinear high-impedance limiting short-circuit current in the series line when the system has an overcurrent due to a short-circuit fault or the like, and can effectively limit the fault current in a very short time. . The self-triggering magnetic bias superconducting current limiter is based on the self-triggering of the non-inductive superconducting coil to realize the first-order current limiting, and then transferred to the double-displacement reactor branch for the second-level current limiting, thereby improving the reliability of the current limiting and avoiding The quench recovery waiting time. Since the parallel strip type YBCO superconducting non-inductive coil adopts a self-tensioning device, the parts are fine and the processing is extremely difficult. Through joint research with Hefei Keju Low Temperature Technology Co., Ltd. and Hefei Kehao Electrophysical Equipment Manufacturing Co., Ltd., an important breakthrough was achieved in the research on the mechanical structure design and key process technology of parallel strip YBCO superconducting non-inductive coils. High-temperature superconducting wire self-tensioning structure design, superconducting non-inductive unit modular integration and superconducting joint welding, etc., provide core technical support for constructing superconducting current limiter, and provide reliable solution for solving short-circuit faults of power grid. The solution is a new technical approach to improve the security of the power grid.
Funded by the State Grid Co., Ltd. “Magnetic Bias Superconductor Current Limiter Operation Experimental Technology Research†technology project, the work was verified by a parallel winding process based on yttrium copper oxynitride (YBCO) high temperature superconducting materials. The technical route of the superconducting non-inductive coil under the tensioned parallel winding structure lays a foundation for the development of the subsequent 10kV high-temperature superconducting current limiter and the experimental demonstration of the network operation.
(Original title: Progress in research on key technologies for preparation of high temperature superconducting current limiters in plasma)