Study of tracking wheel test method under DC voltage

As a simple aging test method for composite insulators, the tracking wheel test has been studied for many years, it is easy to be repeatable due to its simple operation, reproducible results and good equivalence. Recently the tracking wheel test is considered to be published as an IEC standard. More and more composite insulators have been used in HVDC transmission line, and thus their long-term properties are cared. As an aging test method, how about the properties of the tracking wheel test method being used under DC voltage are not clear. In this paper, different voltages such as positive DC voltage, negative DC voltage are applied to the sample to study the DC tracking wheel test. Several kinds of samples are also used in the tests. Comparing with AC tracking wheel test, some differences are shown in the tests, and different samples also show some interesting differences in the test.