Trap characterization in composite of solid-liquid using dual-level trap model and TSDC method

摘要

Charge trap is considered to be one of the effective characteristic parameters for qualitatively evaluating the aging status of insulating material. In this paper, the trap characteristics in oil-impregnated paper with different aging types (non-treatment, thermal treatment and electrical treatment) are investigated using a dual-level (shallow and deep energy) trap model based on space charge profiles and thermally stimulated depolarization current (TSDC) data. The simulated results based on the model are well consistent with the experimental results. Onthe other hand, the TSDC method can acquire much information related to the shallower traps, and the dual–level trap model can obtain much charge dynamicscharacteristics. It has been observed that thermally aging makes the shallow trap energy become deeper while electrically aging makes it shallower. Moreover, thetrap density in oil-impregnated paper increases after aging regardless of thermal or electrical aging.