1.1 本试验方法描述了测定绝缘液体试样击穿电压的两个程序A和B。击穿测试使用45至65 Hz工频范围内的交流电压。 1.2 本试验方法用于测定使用中的电气液体的放电电压。在收到新的绝缘液体后，它不再适用，在这种情况下，测试方法 D1816 应使用。 注1: 据了解，该测试方法存在长期历史，但由于存在许多影响其有效性的缺陷，因此该测试方法不再适用。 建议将所有新的和在用的电绝缘液体放电电压测试移至测试方法 D1816 . 1.3 程序限制: 1.3.1 当本试验方法中使用的施加试验电压大于约25 kV rms时，本试验方法对液体样品中存在的污染物总体的敏感性降低。 1.3.2 如果室温下样品中水的浓度低于饱和度的60%，则该测试方法对水存在的敏感性会降低。有关更多信息，请参阅RR: D27-1006。 2. 1.3.3 对于40°C下粘度高于900 cSt的液体，尚未确定该测试方法的适用性。 1.4 程序申请 1.4.1 程序A: 1.4.1.1 程序A用于确定液体的击穿电压，在所需的重复击穿测试之间的间隔内，任何不溶性击穿产物都很容易在液体中沉淀。这些液体包括石油、碳氢化合物、天然和合成酯，以及用作变压器、电缆和类似设备中的绝缘和冷却液体的askarels（PCB）。 1.4.1.2 程序A可用于获得试验方法中规定的硅油的介电击穿 D2225 ，前提是连续五次击穿时，每次击穿进入样品的放电能量小于20mJ（毫焦耳）。 1.4.2 程序B: 1.4.2.1 本程序用于确定液体的击穿电压，其中任何不溶性击穿产物在程序A要求的1分钟间隔内没有完全从盘之间的空间沉淀出来。程序B根据试验方法第17节进行了修改 D2225 ，如果满足以下要求，则可用于测试硅酮介电液体 1.4.1.2 无法实现。 1.4.2.2 程序B也应适用于测定含有不溶性物质的液体样品的击穿电压，这些物质在测试过程中从样品中沉淀出来。 这些可能包括从断路器、负载分接开关和其他被不溶性颗粒物质严重污染的液体中取样。这些示例代表了重复测试之间可能存在较大差异的样本。在测试此类液体时，使用程序B将获得更准确的击穿电压值。 1.4.2.3 在不存在ASTM规范的情况下或为ASTM指南或标准制定值时，使用程序B确定绝缘液体的击穿电压。一旦单个操作员的精度达到 13.1 已经证明了。 1.5 以国际单位制或英寸-磅单位表示的值应单独视为标准值。每个系统中所述的值不一定是完全等效的；因此，为确保符合标准，每个系统应独立使用，两个系统的值不得组合。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如果有的话）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 =====意义和用途====== 3.1 电介质击穿电压是绝缘液体承受电应力能力的度量。液体的工频击穿电压因纤维素纤维、导电颗粒、污垢和水等污染物的存在而降低。 该测试方法的低结果表明，被测液体中存在一种或多种显著浓度的污染物。请参阅 附录X1 . 3.2 在该测试方法中测量的高击穿电压不一定表明取样液体中存在的污染物量足够低，以至于取样液体在所有电气设备中都是可接受的。试验方法 D877 对低水平的这些污染物不敏感。该测试方法中的故障主要由电极边缘发生的事件决定。 本试验方法中使用的平行盘电极之间的电压应力分布是准均匀的，在平盘面的锐边处存在大量应力集中。 3.3 本试验方法可用于评估供应商交付的用于填充未加工液体的设备中的绝缘液体。 3.4 不建议使用本试验方法来评估设备中使用的液体的击穿电压，这些设备在投入使用前需要应用真空和过滤油。试验方法 D1816 应用于确定过滤和脱气液体的击穿电压。 3.5 本试验方法用于实验室或现场试验。为了使现场分解结果与实验室结果具有可比性，必须满足包括室温（20至30°C）在内的所有标准。

1.1 This test method describes two procedures, A and B, for determining the electrical breakdown voltage of insulating liquid specimens. The breakdown test uses ac voltage in the power-frequency range from 45 to 65 Hz. 1.2 This test method is used to determine the electrical discharge voltage of in-use electrical liquids. It is no longer applicable to new insulating liquids upon receipt, in which case Test Method D1816 shall be used. Note 1: It is understood that long-term histories for this test method exist, but this test method is no longer considered applicable as numerous deficits exist that affect its usefulness. It is recommended to move all new and in-service electrical discharge voltage testing of electrical insulating liquids to Test Method D1816 . 1.3 Limitations of the Procedures: 1.3.1 The sensitivity of this test method to the general population of contaminants present in a liquid sample decreases as applied test voltages used in this test method become greater than approximately 25 kV rms. 1.3.2 If the concentration of water in the sample at room temperature is less than 60 % of saturation, the sensitivity of this test method to the presence of water is decreased. For further information refer to RR:D27-1006. 2 1.3.3 The suitability for this test method has not been determined for a liquid's viscosity higher than 900 cSt at 40 °C. 1.4 Procedure Applications 1.4.1 Procedure A: 1.4.1.1 Procedure A is used to determine the breakdown voltage of liquids in which any insoluble breakdown products easily settle during the interval between the required repeated breakdown tests. These liquids include petroleum oils, hydrocarbons, natural and synthetic esters, and askarels (PCB) used as insulating and cooling liquids in transformers, cables, and similar apparatus. 1.4.1.2 Procedure A may be used to obtain the dielectric breakdown of silicone fluid as specified in Test Methods D2225 , provided the discharge energy into the sample is less than 20 mJ (milli joule) per breakdown for five consecutive breakdowns. 1.4.2 Procedure B: 1.4.2.1 This procedure is used to determine the breakdown voltage of liquids in which any insoluble breakdown products do not completely settle from the space between the disks during the 1-min interval required in Procedure A. Procedure B, modified in accordance with Section 17 of Test Methods D2225 , is acceptable for testing silicone dielectric liquids if the requirements of 1.4.1.2 can not be achieved. 1.4.2.2 Procedure B should also be applied for the determination of the breakdown voltage of liquid samples containing insoluble materials that settle from the specimen during testing. These may include samples taken from circuit breakers, load tap changers, and other liquids heavily contaminated with insoluble particulate material. These examples represent samples that may have large differences between replicate tests. The use of Procedure B will result in a more accurate value of breakdown voltage when testing such liquids. 1.4.2.3 Use Procedure B to establish the breakdown voltage of an insulating liquid where an ASTM specification does not exist or when developing a value for an ASTM guide or standard. Procedure A may be used once the single operator precision of 13.1 has been demonstrated. 1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 3.1 The dielectric breakdown voltage is a measure of the ability of an insulating liquid to withstand electrical stress. The power-frequency breakdown voltage of a liquid is reduced by the presence of contaminants such as cellulosic fibers, conducting particles, dirt, and water. A low result in this test method indicates the presence of significant concentrations of one or more of these contaminants in the liquid tested. See Appendix X1 . 3.2 A high breakdown voltage measured in this test method does not necessarily indicate that the amount of the contaminants present in a liquid from which the sample was taken is sufficiently low for the sampled liquid to be acceptable in all electrical equipment. Test Method D877 is not sensitive to low levels of these contaminants. Breakdown in this test method is dominated by events occurring at the electrode edges. The voltage stress distribution between the parallel disk electrodes used in this test method are quasi-uniform and there is substantial stress concentration at the sharp edges of the flat disk faces. 3.3 This test method may be used for evaluation of insulating liquids in equipment that is designed to be filled with unprocessed liquids as delivered by a vendor. 3.4 This test method is not recommended for evaluation of the breakdown voltage of liquids used in equipment that requires the application of vacuum and filtering of the oil before being placed into service. Test Method D1816 should be used to determine the breakdown voltage of filtered and degassed liquids. 3.5 This test method is used in laboratory or field tests. For field breakdown results to be comparable to laboratory results, all criteria including room temperature (20 to 30 °C) must be met.