A Testing Framework for Investigating Surface Arcing on High Voltage Insulation Systems for Electrified Aircraft Applications

This paper investigates the surface arcing failures on high voltage insulation systems used in electrified aircraft applications, through a proposed testing framework. The framework facilitates the creation of surface arcing under controlled atmospheric pressure conditions, with a capability to test under either AC or DC voltage modes. A high frequency current transformer (HFCT) is also utilized to capture surface discharges (SD) prior to arcing as part of the test. At a given fixed electrode distance, the obtained results suggest earlier inception voltages for both the SD and arcing with decreasing pressures mimicking increasing altitudes. Moreover, the difference in the inception voltage between the SD and arcing diminishes with decreasing pressure, until the difference becomes negligible at pressures corresponding to 4 km above sea level, thereby suggesting an increased risk of using SD detection as means to foresee subsequent arcing. Further testing is conducted to compare between AC and DC arcing. Preliminary results suggest a higher drop for the arcing voltage for DC voltage mode as compared to AC with increasing altitude. These preliminary outcomes could potentially help develop a diagnostic method for arcing failures of insulation systems in electrified aircraft applications.