Space charge dynamics in LDPE films immediately before breakdown

Bipolar model for electrical breakdown in polyethylene materials under dc high electrical fields

“…Based on the hypothesis of unidirectional problem, formulated in the previous section, the coupled equations are one-dimensional and then they are supposed depending only on the 'x' coordinate. These equations are adopted by some previous works in order to study the bipolar charge transport in the LDPE material [12,13,15,17]. Although the LDPE insulating material is composed of crystalline and amorphous phases that are nested, some previous works show that this material is characterized by a chemical homogeneity [20].…”

“…Under high dc applied voltages, the degradation of the LDPE insulating can induce the establishment of the electrical breakdown of the material [9,14]. A relationship between the space charge accumulation and the electrical breakdown in the insulation material has been discussed previously [11,12]. Unfortunately, the corresponding mechanisms of the electrical breakdown phenomenon remain unclear.…”

Leakage current and trapped charge characteristics for glass insulator string under contaminated conditions

“…Though this work shows negative distribution pattern for charge, it is important to articulate that if there is positive charge distribution trend, it indicates breakdown process has already begun [12]. In other cases, positive and negative charge distribution trend is found in [5,13] which suggests that the polarity of charge swinging occurs at the center of the suspension string insulator in their study.…”

Effect of diffusion on space charge formation in dielectrics under steady-state DC conditions

“…Ever since pulsed electro-acoustic method has been invented for space charge measurements [1], due to the ease of application of the method, experimental results of charge formation in dielectrics became abundant and threw new challenges on understanding of different charge phenomena [2][3][4][5][6]. Homo, hetero and packet-like space charges are observed in dielectrics -especially in polymers like LDPE (Low density polyethylene) and XLPE (cross-linked polyethylene).…”