Partial-discharge testing of components for low-voltage equipment

The present test methods and requirements for solid insulation are discussed. It is demonstrated, that those tests and thickness requirements cannot guarantee safe performance of solid insulation throughout the whole equipment life. Moreover, such tests may cause severe damage is applied as a sampling or a routine test. As a replacement, the partial discharge test is proposed. Its applications for testing of transformers, optocouplers, coatings and similar arrangements is demonstrated. It is shown that this test method in combination with conditioning is appropriate for nondestructive testing of solid insulation