电气绝缘系统 热评估程序 第2部分：选择适当的测试方法对电气绝缘系统进行评估和分类

[中文适用范围]： 本部分IEC 61857是一份技术报告，提供了识别适用于评估拟议电气绝缘系统（EIS）的标准的指南。其中一些标准使用单一应力因素（热）来评估EIS。其他标准在诊断测试前调整条件以模拟空气中的应用来评估热应力因素。第三组标准适用于非空气中的应用。 本文件适用于IEC标准中广泛工作电压范围内的现有或拟议EIS。本文件根据结构和预期工作应用识别适当的标准。 [外文原描述]： IEC TR 61857-2:2025 gives guidelines to identify the appropriate test method for the evaluation of a proposed electrical insulation system (EIS). Some of the standards evaluate the EIS using one stress factor which is thermal. Other standards evaluate the thermal stress factor with adjustments to the conditioning applied prior to the diagnostic testing to simulate applications in air. A third group of these standards when the application is other than in air. This technical report is applicable to existing or proposed EIS used in electrotechnical products across a wide range of operating voltages of IEC Standards. The report takes care to identify the appropriate standard based on construction and intended operating application. For all performance and safety requirements related to an application, refer to the technical committee requirements for the application. This edition includes the following significant technical changes with respect to the previous edition. a) The Introduction is expanded to convey that both TC 112 and TC 2 have established EIS test standards. b) Clause 4 introduces the fact that there are four stress factors, not only thermal. This essential concept carries over into part of Clause 5. c) The large number of established standards are organized into common concept groups in Tables 1 to 5: 1) Table 1 covers an overview of EIS evaluations for background and structure. 2) Table 2 covers evaluation of test objects prior to the start of long-term thermal ageing using screening tests. 3) Table 3 covers test standards for the evaluation of thermal stresses in air and has an increased number of standards. 4) Table 4 covers standards for special environmental applications other than in air 5) Table 5 covers standards for the modification of an established EIS.