Research On The Shutdown Characteristics Of Rectangular Double Sided Superconducting Thin Film Switch

The superconducting switch is a closed loop operation with the zero resistance characteristic of the superconductor, and the circuit breaker switch can be realized by using the principle of the super conductor to lose the super resistance. In the current research and application, the superconducting switch is made of low temperature superconducting material and the first generation Bi system high temperature superconducting tape. Cryogenic superconducting materials have lower critical temperature, work in liquid helium temperature region in general situation, and have higher operating costs. The critical current of Bi high temperature superconducting strip is easily influenced by the magnetic field due to its strong anisotropy.But rectangular double sided superconducting thin films can be worked in liquid nitrogen environment,it’s simple to manufacture and has small volume and light weight, is not easy to be affected by the magnetic field. So in this paper, we use rectangular double sided superconducting thin film as the switch.In this paper, we first introduce the concept of rectangular double sided superconducting thin film switch. The switching element is designed on both sides of the lanthanum aluminate (LaA103) substrate layer. This kind of double structure has important physical meaning. First, the thin film is different from the circular superconducting thin film.The rectangular superconducting thin film has a certain length and width.The corresponding voltage and current level can be realized through the linear connection of the superconducting film.It’s no need to design conductive graphics,so it has simple design steps.Second, When the double sided superconducting switches work at the same time, the integration degree of the superconducting switch can be further improved.This reduces the amount of lanthanum aluminate (LaA103) base layer.In this paper, a rectangular double side structure film switch which is 4cm* 1cm, moduled with lanthanum aluminate (LaA103) as the base layer is designed. We analyze the turn off characteristics of the rectangular thin film switch through simulation and experiment. Firstly, the current carrying mode of the normal working state of the rectangular double side superconducting thin film is studied.The simulation results show that the AC loss of rectangular double side superconducting thin film is low and has a very good current carrying performance. Secondly, the 4cm* 1cm size of the rectangular double-sided superconducting thin film switch module was put into 50V,70V,90V three kinds of impact voltage situation of the short circuit experiment. The experimental results show that the switching loss of rectangular double side superconducting thin film is very good.It has a good loss of synchronization characteristics.Then we calculate the quench propagation speed in the multi group impact voltage level. Thirdly, the quench recovery experiments of the rectangular double film superconducting thin film switch are carried out at higher impulse voltage and obtain the quench recovery time of the switch under different voltage. The results show that the recovery time of the rectangular double sided superconducting thin film has a proportional relation to the amplitude and time of the impulse voltage. Finally, based on the theoretical analysis of the above experiments, the short circuit turn off experiment is carried out under various impulse voltages to the switch.Through calculating the quench propagation velocity of the superconducting switch,we obtain the maximum acceptable voltage of the switch.In this paper, a comprehensive study is made on the three processes of the normal operation, the failure and the failure of the rectangular double side superconducting thin film switch.We almost master the quench characteristics of rectangular double sided superconducting thin film switches and verify the feasibility of the circuit breaker of the superconducting thin film switch.At present, due to technical and cost,the preparation of large area superconducting thin film still has many problems. So the superconducting thin film is mainly used in the experimental test of the low voltage level. But with the improvement of scientific research level, superconducting thin films have broad prospects for development in the study of high voltage levels.