Positive corona inception field strength for high-voltage aviation power cable under variable atmospheric conditions

When the traditional aircraft gradually developed into an electric aircraft, the voltage level of megawatt electric aircraft has jumped to kilovolt level, which will inevitably induce corona discharge of high-voltage aviation power cables, which will bring various hazards to the airworthiness safety of aviation cables. In order to solve this problem, considering that the corona inception field strength is an important parameter to reflect the corona inception of the cable, this paper proposes a calculation method to estimate the initial field strength of the positive corona of the cable. This method is based on the streamer theory. The initial field strength is determined using the known electric field distribution and the effective ionization coefficient derived by Hartmann expression. Changing the cable radius and considering varying atmospheric conditions, the method yields a corona onset field strength consistent with existing experimental data at the avalanche electron number of 10^4. Then, in order to accurately estimate the field strength of the cable in the case of humidity, the Peek formula is modified by introducing the absolute humidity factor.