Research on the discharge characteristics for water tree in crosslinked polyethylene cable based on plasma-chemical model

Abstract

Water tree is the predominant defect in high-voltage crosslinked polyethylene cables. The microscopic mechanism in the discharge process is not fully understood; hence, a drawback is created towards an effective method to evaluate the insulation status. In order to investigate the growth of water tree, a plasma-chemical model is developed. The dynamic characteristics of the discharge process including voltage waveform, current waveform, electron density, electric potential, and electric field intensity are analyzed. Our results show that the distorted electric field is the predominant contributing factor of electron avalanche formation, which inevitably leads to the formation of pulse current. In addition, it is found that characteristic parameters such as the pulse width and pulse number have a great relevance to the length of water tree. Accordingly, the growth of water tree can be divided into the initial stage, development stage, and pre-breakdown stage, which provides a reference for evaluating the deteriorated stages of crosslinked polyethylene cables.

Assessment on capacity expansion of AC XLPE cable under DC operation with the constraint of temperature and electric field intensity

“…The purpose of this research is to modify the parameters of operational voltage after the AC-DC transformation of cables, but it is easy to form a local high field electric intensity in the insulation when there is an air gap or moisture in it [15]. And space charge could accumulate in XLPE insulation, which can accelerate insulation degradation, even lead to breakdown accident [16,17].…”

Study on the Propagation Characteristics of Partial Discharge in Switchgear Based on Near-Field to Far-Field Transformation

“…Currently, a number of researchers have proposed some fluid chemistry models, which are used to describe the phenomenon of PD [20][21][22][23]. Peng Qingjun and Zhang Yun established a hydrodynamic drift-diffusion model to describe the spatial-temporal evolution of electrons and ions in the discharge process, in which they obtained the radiation of EM waves propagated into the space.…”