Значение и использование
This is a laboratory test designed to simulate the effects of (1) the presence of rough interfaces between conductor or semiconductive screen and primary insulation in an insulation system, (2) the presence of foreign particles (contaminants) in an insulation system, and (3) the presence of small voids or cavities within the insulation.
This test method provides comparative data. The degree of correlation with actual performance in service has not been established.
1.1 This test method covers the evaluation andcomparison of the resistance of solid organic dielectric materialsto the initiation or growth, or both, of tubular tree-like channelsresulting from partial discharge (corona) and moleculardecomposition that occur in the region of very high, divergingelectric fields. ,
1.2 This test method is primarily for use at a powerfrequency of 50 or 60 Hz.
1.3 The test may be carried out at room temperatureor temperatures above or below room temperature. The temperatureshould not exceed the softening or melting point of the samplematerial.
1.4 This test method can be used for any solidmaterial into which needles can be cast, molded, or inserted withheat after molding. The resistance to tree initiation is measuredby the double-needle characteristic voltage, which is onlyapplicable to non-opaque materials so that tree can be observedoptically. The resistance to tree initiation and growth is reportedby the double-needle voltage life, which is applicable to bothopaque and non-opaque materials.
1.5 The values stated in SI units are to be regardedas the standard.
1.6 This standard does notpurport to address all of the safety concerns, if any, associatedwith its use. It is the responsibility of the user of this standardto establish appropriate safety and health practices and determinethe applicability of regulatory limitations prior touse.