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 towards 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 paper, 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 characteristics and electrical tree growth characteristics at different stages of electrical tree growth between layers are studied. Partial discharge inception voltage (V_I), and partial discharge extinction voltage (V_X), during the growth of a non-conductive tree are estimated. The quantitative relationship between partial discharge and tree length is investigated. It found that partial discharge maximum magnitude and V_I-V_X and tree length show a linear relationship in the stage of non-conductive tree growth. The ratio of partial discharge maximum magnitude to V_I -V_X and tree length is approximately equal to a constant. To explain the relationship between tree length and partial discharge maximum magnitude, V_I, and V_X in the non-conductive tree, a dynamic PD propagation in non-electric tree model is proposed. This method can quantitatively analyze the electrical defects of power equipment only through partial discharge information. This has great potential for application in the defect assessment of PCBs.