Developmental Research on Prospective Power Transmission System Integrated under Superconducting Environment

该开发研究项目旨在验证下一代超导输电的技术可能性。为此，一个前瞻性的电力传输模型系统集成在超导环境下，简称为PROMISE，已在试验中构建。PROMISE由超导变压器、故障限流器和电缆组成。这三个装置被封闭在一个长尺度的低温恒温器中，以保持它们在液氦温度，4.2 K。其传输容量的目标是6 kV - 1500 kVA。在为期3年的研究项目中进行了6次性能测试。主要结果如下：1.经多次综合试验证明，该装置具有6 kV - 1000 kVA的输电能力，在世界上尚属首次。在高压侧施加6 kV线地电压的情况下，成功地维持了177 A的环流.的 ...更多信息 超导故障限流器实际上表现出良好的限流性能，防止其它设备因故障电流过大而陷入异常失超。这意味着在未来的超导输电中，失超电流水平的协调将通过限流器来实现.建立了854升PROMISE低温恒温器电缆段和变电站段的大体积液氦注入技术。由于沿沿着电源引线的热传导而进入低温恒温器的热侵入占总热侵入的75 - 90%.当超导导线中淬火部分受热而产生大量气泡时，液氦的动态交流耐压水平会急剧下降.液氮的击穿电压存在面积效应和体积效应。采用威布尔分布进行统计分析，结果在理论上得到了支持。少

This developmental research project aims at verifying the technical possibility of superconducting power transmission for the next generation. For this purpose, a prospective power transmission model system integrated under superconduction environment, abbreviated to PROMISE, has been constructed in trial. The PROMISE consists of a superconducting-transformer, -fault current limiter, and -cable. These three apparatus are enclosed in a long scaled cryostat to keep them at the liquid helium temperature, 4.2 K.The target of its transmission capacity is 6 kV - 1500 kVA.Performance tests were carried out 6 times during the 3-year research project. Major results obtained are as follows :1. It has been proved by a few times of synthetic tests that the PROMISE has the transmission capacity of 6 kV - 1000 kVA, which is the first achievement in the world. The circulating current of 177 A was successfully sustained under impression of 6 kV of line-to-ground voltage to the high tension side.2. The … More superconducting fault current limiter actually presented excellent current limiting performance to prevent the other apparatus from falling into abnormal quenching due to large fault current. This means that quenching current level coordination is realized by the current limiter in the future superconducting power transmission.3. The injection technique of large volume of liquid helium was established for the whole PROMISE cryostat of 854 liters with the cable section of 5 m as well as the substation section. The thermal invasion into the cryostat due to heat conduction along the power leads occupies 75 to 90 % of the total one.4. Drastic degradation of dynamic ac voltage withstand level of liquid helium was actually found when a number of bubbles occurred due to heating of quenched part in a superconducting wire.5. The area and volume effects experimentally emerged on the breakdown voltage of liquid nitrogen. The results were theoretically supported with statistical analyzes using Weibull distribution. Less