Small scale arc fault testing of medium voltage metal enclosed switchgear

Internal arc fault tests are important for ensuring the safety of medium-voltage metal-enclosed switchgears. Since these tests are conducted at full scale, the costs of the test objects as well as the high-power laboratory are significant. This paper presents an experimental study to clarify whether such tests can be simplified by downscaling. Tests with volume and energy downscaled to 1/3 and 1/10, respectively, were performed on a single-phase arrangement with air as the insulating gas. The test results showed that the internal pressure rise caused by the arc can be reproduced well using a smaller compartment and lower current. The potential damage caused by the exhaust of the hot gas escaping through the pressure-relief openings is more challenging to predict from small-scale tests.