Development of Superconducting Fault Current Limiting Transformer with HTS Bulk Conductors

我们开发的高温超导故障限流互感器（HTc-SFCLT）兼具超导互感器和超导故障限流器的功能，作为我们SFCLT项目的第三阶段。本文的主要研究结果总结如下：(1)采用MCP-BSCCO2212块体与CuNi复合材料作为HTc-SFCLT的低压线圈，采用铜线作为高压线圈。将HTc-SFCLT与铁芯一起浸泡在液氮中。(2)空载和短路试验结果证实，HTc-SFCLT作为超导变压器具有基本性能和设计参数。(3)限流试验结果表明，HTc-SFCLT作为超导故障限流器具有有效的限流功能。短路后预期短路电流I_<PRO>=800 A_<峰值>可限制为1周期55%，5周期37%。(4)恢复试验结果表明，在故障清除后，HTc-SFCLT能够立即自行成功恢复到超导状态。BSCC02212体线圈在限流过程中的温升估计最多为4 K，即使I_<PRO>=800 A_<峰值>。

We developed HTc-SFCLT (High Temperature Superconducting Fault Current Limiting Transformer) with functions of both superconducting transformer and superconducting fault current limiter as the Phase-3 of our SFCLT project. The main results in this paper are summarized as follows :(1) Composite material of MCP-BSCCO2212 bulk and CuNi was adopted as the low-voltage coil of HTc-SFCLT, whereas copper -wire was adopted as the high-voltage coil. Such a HTc-SFCLT was immersed in liquid nitrogen together with the iron core.(2) No-load and short-circuit test results confirmed that HTc-SFCLT has the fundamental performance with the design parameters as a superconducting transformer.(3) Current limiting test results revealed that HTc-SFCLT has the effective current limiting function as a superconducting fault current limiter. The prospective short-circuit current I_<PRO>=800 A_<peak> could be limited into 55% at 1 cycle and 37% at 5 cycles after short-circuit.(4) Recovery test results suggested that HTc-SFCLT could successfully recover into superconducting state by itself immediately after the fault clearance. The temperature rise of BSCC02212 bulk coil during the current limiting process was estimated to be at most 4 K even for I_<PRO>=800 A_<peak>.