Electrical Treeing and Partial Discharges in Double Layer Printed Circuit Board

With the development of power devices, the demand to improve insulation performance of printed circuit boards (PCBs) is increasing. PCB faces great challenges in its insulation failure caused by long-term ageing when subject to intensive electric fields. It is observed that failures are commonly detected between layers. Therefore, this paper designed and made V-shaped double layer samples to test the partial discharge and electrical tree growth. Based on the method of pulse sequence analysis and phase-revolved partial discharge pattern, the insulation deterioration in layers is analyzed. It was found that the electrical tree grew into branched electrical trees. Based on the PSA, the growth of tree conforms the characteristic of non-conductive electrical tree. The partial discharges inception and extinction voltage decrease at first as the tree grows. But as the electric tree grows, their trend becomes very complex. The apparent charge followed almost linear relationship with the maximum length of electrical tree in the first 5 minutes.