Electrical Tree Initiation and Growth in Silicone Rubber under Combined DC-Pulse Voltage

Abstract

Electrical tree is a serious threat to silicone rubber (SIR) insulation and can even cause breakdown. Electrical trees under alternating current (AC) and direct current (DC) voltage have been widely researched. While there are pulses in high-voltage direct current (HVDC) cables under operating conditions caused by lightning and operating overvoltage in the power system, little research has been reported about trees under combined DC-pulse voltage. Their inception and growth mechanism is still not clear. In this paper, electrical trees are studied under several types of combined DC-pulse voltage. The initiation and growth process was recorded by a digital microscope system. The experimental results indicate that the inception pulse voltage is different under each voltage type and is influenced by the combined DC. The initial tree has two structures, determined by the pulse polarity. With increased DC prestressing time, tree inception pulse voltage with the same polarity is clearly decreased. Moreover, a special initial bubble tree was observed after the prestressing DC.

Effect of Polycyclic Compounds Fillers on Electrical Treeing Characteristics in XLPE with DC-Impulse Voltage

“…After the temperature reached the set temperature during the experiment, the sample was allowed to stand in the incubator for 10 min to ensure that the temperature of the material was consistent with the environment. The DC-impulse voltage was generated by the DC-impulse power source, which consisted of a DC power source and impulse power source [31]. The DC voltage was applied at a rate of 1 kV/s.…”

Selected Papers from 2020 IEEE International Conference on High Voltage Engineering (ICHVE 2020)

“…It is well known that the presence of conductive and non-conductive solid particles inside insulating oils results in the decrease of breakdown voltage [29][30][31][32]. All the relevant studies that have been conducted concern solid particles with sizes of the order of several hundred μm.…”

“…It is difficult for traditional BPNNs to find out the global optimum solution of the prediction application [26,27]. A genetic algorithm (GA) is a method to obtain global optimum solution of the proposed problems based on a natural selection process which mimics the biological evolution process [28][29][30][31]. In this article, GA was used to optimize the weight and the threshold of the BPNN.…”

“…where J e is an externally generated current density, and J e = 0. σ is the collective conductivity of insulation oil and impurities, which is derived according to the Looyenga Formula (31). The static form of the equation of current continuity then reads…”

Inhibition Effect of Graphene Nanoplatelets on Electrical Degradation in Silicone Rubber

“…Silicone rubber (SIR) is usually employed as insulation in both alternating current (AC) and direct current (DC) power cable accessories, forming a multilayer insulation with cross-linked polyethylene (XLPE), polypropylene (PP) or other polymers [1,2,3]. Given the distortion of electric field and manufacturing defects, electrical degradation is easily initiated in SIR [4,5,6]. As a typical electrical degradation, the electrical tree initiation and growth have been widely researched since it was first identified [7,8,9,10].…”