Numerical simulation of the space charge accumulation inside solid insulation subjected to special polarization conditions

This is the authors' abstract. We don't add key points for this paper.

The insulation of high-power electronic equipment faces special electrical stresses such as square and pulse waves, but the numerical research on space charge inside the insulation under such conditions is still in the blank at present. Based on the traditional bipolar charge transport model, it is indicated that the polarization conditions with changing polarities require that the solving algorithms of the model should be selected according to the electric field direction inside the sample grid. The charge phenomena under different sample parameters and polarization conditions in the power frequency range are further simulated. It is concluded that both the total charge amounts under unipolar and bipolar conditions are affected by the polarization power, and the charge migration depth is within 20 μ m. For the sample parameters, it is found that the accumulated charge amount under two types of polar polarization conditions is obviously reduced as the value of injection barrier or extraction coefficient increases. And the trapping and detrapping parameters have a greater influence under unipolar conditions. Therefore, it is necessary to select appropriate modified parameters according to the actual operating conditions when controlling the insulating performance. As for the polarization condition, it is found that the charge amount at high frequencies is unaffected by the frequency value, and a phenomenon that positive and negative charges simultaneously accumulate can be found under all the bipolar conditions with a frequency of 0.01 Hz. In addition, the simulation also indicates that the charge measurement technique needs to have a sufficiently high spatial resolution under these conditions, and the required time to measure the steady charge is relatively shorter under bipolar conditions.