Research On Current Carrying Capacity And AC Loss Characteristics Of HTS Composite Conductor And 3-Channel Conductor

The discovery of high-temperature superconducting(HTS)materials has greatly reduced the cost of superconducting technology applications.The widespread commercialization of second-generation HTS tapes will further expand the market for superconducting technology applications.However,a single HTS tape usually cannot meet the engineering current carrying capacity requirements although that has the advantages of large critical current density than the normal material conductor witch have the same cross-section area.Therefore,many scholars developed a series of HTS conductors,such as conductor on round core(CORC),twisted stacked-tape conductor(TSTC),and quasi-isotropic stand(QIS).The performance of these HTS conductors is sufficient to meet the needs of many practical applications.However,the development of conductors with greater current carrying capacity and lower AC losses can provide more possibilities for HTS technology applications.The current-carrying capacity of a HTS conductor directly determines whether it can meet the needs of practical applications,and its AC loss affects the cooling cost and even the safety of system operation.Therefore,it is of practical significance to study the current-carrying performance and AC loss characteristics of HTS conductors.Therefore,starting from the question of how to improve the current carrying capacity of CORC conductors,this paper studies the current carrying performance of TSTC-CORC composite conductors and QIS-CORC composite conductors,and then studies the differences in the respective AC loss characteristics.Based on the research conclusions of composite conductors.This paper analyzes the differences in current-carrying performance and AC loss characteristics of 3-channel TSTC conductors and 3-channel QIS conductors.The content of this paper is divided into the following points:1.Using the combination of experiment and simulation,explored the difference of critical current of CORC type conductors in different winding directions.First,CORC type conductor samples with different winding directions were maded and tested in a liquid nitrogen environment.Second,this paper proposed the concept of reverse current and be used to simulate the critical current of CORC type conductors with different winding directions in finite element software.Simulation results and experimental results could be consistent;both confirm that CORC-type conductors need to be cross-wound to obtain a higher critical current.Based on the conclusion of the previous research,this paper successfully developed the CORC type conductor with more than 1000 A critical current.2.Based on the results of the CORC type conductors with different winding directions in the previous study and reference the structs of the TSTC-CORC composite conductor and the QIS conductor to propose the QIS-CORC composite conductor.By establishing two-dimensional simulation models of TSTC conductor,QIS conductor,TSTC-CORC composite conductor,and QIS-CORC composite conductor in the finite element software,the critical current and critical current anisotropy of different composite conductors are explored The change in critical current and the AC loss characteristics of composite conductors with different numbers of layers and wound in the same direction.The research summarized the follow points.First,the critical current of the cross-wound composite conductor is greater.Second,the critical current anisotropy of the composite conductor is related to the central conductor.Third,the current carrying performance of the composite conductor when running side by side is not as good as the original conductor.Forth,the central conductor determines the value of composite conductor`s AC loss and the number of outer CORC conductor layers determine the change in the AC loss of the composite conductor.3.Based on the differences in the critical current,critical current anisotropy,and AC loss of the TSTC conductor and QIS conductor that have had been studied in the preview.This paper combines the existing 3-channel TSTC conductor and QIS conductor to propose the3-Channel QIS conductor.Two-dimensional simulation models of two 3-channel conductors are established and simulated in the finite element software.The simulation results show the critical current anisotropy of 3-channel QIS conductor is lower than 3-channel TSTC conductor,and 3-channel QIS conductor produce less AC loss than the later one.Therefore,3-channel QIS conductor has great current carrying capacity and AC loss characteristic.It is a kind of new type HTS conductor and has broad application prospects.