Partial Discharge Characteristics and Growth Stage Recognition of Electrical Tree in XLPE Insulation

Electrical treeing is an inevitable phenomenon during the operation of cross-linked polyethylene (XLPE) cables installed in the underground and humid environment, which is the direct reason for insulation failure. This work focuses on the issue of electrical trees in XLPE insulation and growth stage recognition of treeing stage. The partial discharge (PD) characteristics during different tree growth modes were recorded in the form of $\varphi $ -q-n patterns. A growth model of electrical trees considering PD process was investigated. The discharge energy was computed, and the relationship between PD characteristics and growth modes of electrical trees was analyzed. A recognition method of the growth stages of electrical trees was given. It was found that PD is mainly distributed in the rising stage of applied voltage, which is the typical characteristic of internal discharge. Tree growth speed depends on the discharge energy that periodically changes during treeing. The increase in PD energy promotes the growth of electrical trees. The growth stage of electrical trees in the rapid growth mode can be recognized by the sparse representation with a recognition accuracy of 90%.