绝缘液体氧化稳定性试验方法评估绝缘液体交货状态下氧化稳定性的试验方法

[中文适用范围]： 本文档描述了一种评估绝缘油在交付状态下氧化稳定性的测试方法，该方法在加速条件下进行，无论是否含有抗氧化添加剂。测试持续时间可能因绝缘油类型而异，并由相应标准（如 IEC 60296、IEC 61099、IEC 62770）定义。该方法可用于测量诱导期，测试持续至挥发性酸度显著超过 0.10 mg KOH/g（矿物油情况）；酯类液体的该值可能显著更高。将绝缘油样品在 120°C 下保持，同时存在固体铜催化剂并通入恒定流量的空气。氧化稳定程度通过测量挥发性酸度、可溶酸度、油泥、介质损耗因数，或产生给定量挥发性酸度所需的时间（空气诱导期）来估计。在资料性附录 B 中，描述了一种通过测量氧诱导期来评估抑制型矿物绝缘油在交付状态下氧化稳定性的测试方法。该方法仅旨在用于质量控制。结果不一定提供关于服务性能的信息。将油样品在 120°C 下保持，同时存在固体铜催化剂并通入恒定流量的氧气。氧化稳定程度通过油产生确定量挥发性酸度所需的时间（氧诱导期）来估计。在指定持续时间后，还可测定其他标准，如可溶和挥发性酸度、油泥和介质损耗因数。在资料性附录 C 中，描述了一种旨在模拟酯类绝缘油热氧化行为的测试方法（150°C 下空气顶空 164 小时）。此外，还可以使用如 IEC TR 62036 中描述的基于差示扫描量热法的其他测试方法作为筛选测试，但这些方法不在本文档范围内。 [外文原描述]： IEC 61125:2018 describes a test method for evaluating the oxidation stability of insulating liquids in the delivered state under accelerated conditions regardless of whether or not antioxidant additives are present. The duration of the test can be different depending on the insulating liquid type and is defined in the corresponding standards (e.g. in IEC 60296, IEC 61099, IEC 62770). The method can be used for measuring the induction period, the test being continued until the volatile acidity significantly exceeds 0,10 mg KOH/g in the case of mineral oils. This value can be significantly higher in the case of ester liquids. Additional test methods such as those described in IEC TR 62036 based on differential scanning calorimetry can also be used as screening tests, but are out of the scope of this document. This second edition cancels and replaces the first edition published in 1992 and Amendment 1: 2004. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the title has been modified to include insulating liquids different from mineral insulating oils (hydrocarbon); b) the method applies for insulating liquids in the delivered state; c) former Method C is now the main normative method; d) precision data of the main normative method has been updated concerning the dissipation factor; e) former Method A has been deleted; f) former Method B has been transferred to Annex B; g) a new method evaluating the thermo-oxidative behaviour of esters is included in Annex C.