1.1 本试验方法涵盖了固体半透明热塑性或交联电绝缘材料中通气水树生长的相对电阻。本试验方法特别适用于中压电缆中使用的挤压聚合物绝缘材料。 1.2 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 有关具体的危险声明，请参见 8.1 . 1.4 没有类似或等效的IEC标准。 ====意义和用途====== 5.1 这是一项实验室试验，旨在模拟在高电场的潮湿环境下，由绝缘和导电界面处的尖锐突起引发的固体电介质绝缘材料中通风水树的生长。水树现象是指有机电介质在交流电场下暴露于潮湿环境时出现树状生长的现象。形成了两种类型的水树。由导电/绝缘材料界面进入绝缘材料形成的蝶形树（电介质内）和通风水树。本试验方法中提及的水树为通风型。绝缘材料为固体电介质有机材料。导电材料是盐溶液。 该盐溶液用于绝缘材料的两侧，以模拟中压地下电力电缆中使用的绝缘层之间的相同内、外半导体屏蔽层，该屏蔽层被水分饱和。 5.2 本试验方法提供了比较数据。与服务绩效的相关程度尚未确定。 5.3 标准测试条件旨在在发生电气击穿之前，为大多数感兴趣的固体电介质绝缘材料生长足够的水树长度。具有极高抗水树生长能力的材料在测试条件下（例如180天）或更高电压（例如10或15 kV）需要更长的时间，以区分其性能。对于耐水性极低的材料- 在大多数情况下，在30天的测试时间内，树木生长、电气故障都会发生。建议缩短测试时间（如一天或十天），以防止在测试这些低水树抗性材料时发生电击穿。 5.4 其他电压、频率、温度、水溶液和缺陷可用于评估特定应用的特定材料。温度不得超过材料的软化点或熔点，或低于盐溶液沸点10至15℃。任何非标准条件应与结果一起报告。 5.5 树木生长率通常随测试频率而增加。由频率引起的加速度系数由下式得出:( f /60) k 哪里 f 是测试频率和 k 介于0.6和0.7之间。选择1 kHz的测试频率来加速水树的生长。然而，在不同的频率范围内，水树氧化产物的化学性质可能不同。 5.6 本试验方法的两个假设是:( 1. )所有测试材料以相同的幂律动力学方式生长树木( 2. )在30天的测试条件下，足够长的时间来确定水树生长的差异。如果有疑问，应使用至少三个不同的测试时间（如30、90和180天）来验证其比较性能，并披露其水树生长的动力学性质。当然，还假设所有水树区域都是氧化区域，可以对其进行染色以进行光学观察。 不同材料的软化温度将需要不同的温度和时间来着色氧化（treed）区域。

1.1 This test method covers the relative resistance to vented water-tree growth in solid translucent thermoplastic or cross-linked electrical insulating materials. This test method is especially applicable to extruded polymeric insulation materials used in medium-voltage cables. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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 and health practices and determine the applicability of regulatory limitation prior to use. For specific hazard statements see 8.1 . 1.4 There is no similar or equivalent IEC standard. ====== Significance And Use ====== 5.1 This is a laboratory test designed to simulate the growth of vented water-trees in the solid dielectric insulating material initiated by a sharp protrusion at the insulating and conductive interface under a wet environment in a high electrical field. Water-treeing is the phenomenon which describes the appearance of tree-like growth in organic dielectrics under an ac field when exposed to moist environments. Two types of water-trees are formed. Bow tie trees (within the dielectric) and vented water-trees formed from conductive/insulating material interface into the insulating material. The water-trees referred to in this test method are the vented type. The insulating material is the solid dielectric organic material. The conductive material is the salt solution. This salt solution is used on both sides of the insulating material to simulate the same inner and outer semiconductive shields saturated with moisture between the insulation layer used in a medium-voltage underground power cable. 5.2 This test method provides comparative data. The degree of correlation with the performance in service has not been established. 5.3 The standard test conditions are designed to grow a sufficient water-tree length for most solid dielectric insulating materials of interest before electrical breakdown occurs. Materials with a very high resistance to water-tree growth require a longer time under test conditions (such as 180 days) or higher voltage (such as 10 or 15 kV) in order to differentiate their performance. For materials with a very low resistance to water-tree growth, electrical breakdown will occur during the 30-day testing time in most instances. A shorter testing time (such as one or ten days) is recommended to prevent electrical breakdown during testing for those low water-tree resistant materials. 5.4 Other voltages, frequencies, temperatures, aqueous solutions, and defects are able to be used to evaluate specific materials for specific applications. Temperatures shall not exceed the softening or melting point of the material or 10 to 15°C below the boiling point of the salt solution. Any nonstandard conditions shall be reported along with the results. 5.5 Tree-growth rates generally increase with the test frequency. An acceleration factor due to frequency is given by ( f /60) k where f is the test frequency and k is between 0.6 and 0.7. The test frequency of 1 kHz is selected to accelerate the water-tree growth. However, there is the possibility that the chemical nature of oxidized products from water-treeing may be different at different frequency ranges. 5.6 Two assumptions for this test method are: ( 1 ) all tested materials grow trees in the same power law kinetic manner and ( 2 ) the time under test conditions of 30 days is long enough to establish the difference in water-tree growth. If there is a doubt, at least three different testing times (such as 30, 90, and 180 days) shall be used to verify their comparative performance and disclose their kinetic nature of water-tree growth. Of course, it is also assumed that all water-treed regions are oxidized regions that are able to be stained for optical observation. The softening temperature of different materials will require different temperature and times to stain the oxidized (treed) regions.