Quantitative Analysis of Electrical Tree Growth With Partial Discharge Characteristics of PCB Double Layer Under AC Voltage

With the development of electronic technology, electronic devices are moving toward high power and miniaturization. Printed circuit board (PCB), as an important insulation support in electronic devices, is difficult to meet the development needs of power electronic devices. As an important insulation degradation phenomenon, the electric tree is also detected in PCBs. However, the issue of insulation degradation between PCB layers has not been thoroughly studied. In this article, a V-shape double-layer electrode is designed to investigate the insulation failure caused by the electrical tree between layers of PCB. By analyzing the phase-resolved partial discharge (PRPD) pattern and voltage difference (dV) plots of electrical tree growth, the partial discharge (PD) characteristics and electrical tree growth characteristics at different stages of electrical tree growth between layers are studied. PD inception voltage (PDIV) (V_I) and PD extinction voltage (V_X) during the growth of a nonconductive tree are estimated. The quantitative relationship between PD and tree length is investigated. It is found that PD maximum magnitude and V_I-V_X and tree length show a linear relationship in the stage of nonconductive tree growth. The ratio of PD maximum magnitude to V_I-V_X and tree length is approximately equal to a constant. To explain the relationship between tree length and PD maximum magnitude, V_I and V_X in the non-conductive tree, a dynamic PD propagation in nonelectric tree model is proposed. This method can quantitatively analyze the electrical defects of power equipment only through PD information. This has great potential for application in the defect assessment of PCBs.