Experimental Study On AC Loss Of A Novel HTS Short-Sample Cable

With the development of high-temperature superconducting transmission technology,a revolution in the power industry has also begun.High-temperature superconducting(HTS)transmission line has become the most promising power engineering technology due to its characteristics of large carrying current and small volume.When HTS cable is used in practical engineering,it will be in the working environment of alternating magnetic field and alternating current with different size,which will cause the AC loss inside the superconducting cable.At the same time,in the process of equipment manufacturing and use,superconducting wire will be subjected to a variety of stresses in different environments.This paper chooses the second generation of YBCO strip made of novel high-temperature superconducting square wire,because it is 1 mm ×1 mm square cross-section of special structure,especially in the twisting process,on the width and height direction can better keep single strand rectangular line by torsion is the same,at the same time on the length direction can ensure more shares square wire by torsion were distributed evenly,This not only increases the current carrying capacity of the superconducting strip but also reduces the limitation of physical conditions,so that it can be applied to different superconducting equipment.Through a series of preparation processes such as cutting and packaging,the required novel high-temperature superconducting square wire of 4s+2c specification was obtained,and the AC loss characteristics of this high-temperature superconducting square wire were analyzed,and two types of high-temperature superconducting short sample cables were prepared by using it,which can be used in two kinds of throughflow mode experiments respectively.Among them,the selection of supporting device materials for short-sample cables has also been compared and tested.Finally,epoxy resin materials with less influence on AC loss are selected as supporting devices for short-sample cables.Finally,AC losses of various short-sample cables under different through-flow modes and twist pitches are measured by experimental methods,and the influences of various through-flow modes and twist pitches on AC losses of shortsample cables are analyzed.After comparing the test results,it is concluded that the twisted structure of the two types of short-sample cables can reduce their AC losses.Although the first type of parallel current mode can effectively reduce AC losses,the distribution relationship of the internal current of short-sample cables is very random due to the parallel connection of multiple square wire.The second type of series current mode ensures that the currents of multiple square wire in short-sample cables must be in the same phase.At the same time,the two types of current modes have mutual inductance effects,but the second type of series current mode.In terms of twist pitch,the AC loss of the first type of parallel-connected short-sample cable is relatively lower,and the minimum twist pitch is smaller,which is more conducive to practical engineering application than the second type of series-connected short-sample cables.