IEC 61788-4:20 20 RLV包含官方IEC国际标准及其红线版本。Redline版本不是官方文档，它只有英文版本，为您提供了一种快速简单的方法来比较IEC官方标准与其以前版本之间的所有变化。 IEC 61788-4:20 20规定了在无应变条件和零外部磁场下测定具有Cu、Cu-Ni、Cu/Cu-Ni和Al基体的Nb-Ti和Nb3Sn复合超导体的残余电阻比（RRR）的试验方法。该方法旨在用于具有矩形或圆形横截面的整体结构、RRR值小于350且横截面面积小于3mm2的超导体样品。在Nb3Sn的情况下，样品已经接受了反应热-治疗。这第五版取消并取代了2016年出版的第四版。本版构成技术修订版。与上一版相比，此版本包括以下重大技术变更: a)样品上用于可靠测量的电压抽头的合适距离的变化， b)证明本标准中测量方法有效性的Nb3Sn超导体剩余电阻比循环试验结果的新报告， c)修订铜比率和铜分数的混淆定义。

IEC 61788-4:2020 RLV contains both the official IEC International Standard and its Redline version. The Redline version is not an official document, it is available in English only and provides you with a quick and easy way to compare all the changes between the official IEC Standard and its previous edition. IEC 61788-4:2020 specifies a test method for the determination of the residual resistance ratio (RRR) of Nb-Ti and Nb3Sn composite superconductors with Cu, Cu-Ni, Cu/Cu-Ni and Al matrix in a strain-free condition and zero external magnetic field. This method is intended for use with superconductor specimens that have a monolithic structure with rectangular or round cross-section, RRR value less than 350, and cross-sectional area less than 3 mm2. In the case of Nb3Sn, the specimens have received a reaction heat-treatment. This fifth edition cancels and replaces the fourth edition published in 2016. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) change in the suitable distance of voltage taps on the specimen for reliable measurement,
b) new report on the result of the round robin test of the residual resistance ratio of Nb3Sn superconductors that proves the validity of the measurement method in this standard,
c) revision of the confusing definitions of the copper ratio and copper fraction.