4.1 These test methods differentiate among solid electrical insulating materials on the basis of their resistance to the action of voltage stresses along the surface of the solid when wet with an ionizable, electrically conductive liquid contaminant.
4.2 These test methods quantitatively evaluate, in a relative manner, the effects upon an insulating material resulting from the action of electrical discharges upon a material surface. The effects are similar to those that may occur in service under the influence of dirt combined with moisture condensed from the atmosphere.
4.2.1 In the field, the conditions resulting in electrical discharges occur sporadically. Degradation, often in the form of a conducting “track,” develops very slowly until it ultimately bridges the space between conductors thus causing complete electrical breakdown.
4.2.2 In these test methods, the conducting liquid contaminant is continuously supplied at an optimum rate to the surface of a test specimen in such a fashion that essentially continuous electrical discharge can be maintained.
4.3 The time-to-track a 1-in. (25-mm) distance at a specified voltage between electrodes separated 2 in. (50 mm) has also been found useful in categorizing insulating materials for indoor and protected outdoor applications, such as metal-clad switchgear.
4.4 The initial tracking voltage has been found useful for evaluating insulating materials to be used at high voltages or outdoors and unprotected, as well as for establishing (see 10.1) the test voltage for the time-to-track test.
4.5 In service many types of contamination cause tracking and erosion of different materials to different degrees. This method recognizes the importance of such variability and suggests the use of special test solutions to meet specific service needs. For example, an ionic contaminant containing, in addition, a carbonaceous component such as sugar is substituted to cause tracking on very resistant materials like polymethylmethacrylate. Such contamination is considered representative of some severe industrial environments. In this case, the time-to-track technique is used, since time is required to decompose the contaminant solution and build up conducting residues on the sample surface.
4.6 Very track-resistant materials, such as polymethylmethacrylate, typically erodes rather than track under more usual contaminant conditions in service. The use of this method for measuring erosion is consequently important. For erosion studies, only tests as a function of time at constant voltage are usefu......
高压漏电起痕试验仪和漏电起痕试验仪都是用来检测绝缘材料某一物理性能的测试设备,但两者所检测的物理性能却是不一样的,因此两者所依据的试验标准也是不一样的。一、定义区别 高压漏电起痕试验仪是模拟在工频(48Hz - 62Hz)下,用液体污染物和斜面试样,通过耐电痕化和蚀损的测量评定在严酷环境条件下使用的电气绝缘材料的耐电痕化和蚀损等级。...
电工产品中使用的多种固体绝缘材料在电场和污染液联合作用下,常常会形成导电通道——“漏电痕迹”和电腐蚀引起电气短路,有些材料甚至会燃烧起火,严重危及电工产品在铁路、石油、化工、煤矿、船舶、航天、通信广播……等有防燃防爆要求部门的可靠使用。绝缘材料通过CTI值测定能向设计人员提供选用材料的漏电起痕数据,对于优化电气产品设计,提供产品可靠性有重要意义。 ...
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