Electrical treeing behaviors in silicone rubber under an impulse voltage considering high temperature

Abstract

In this paper, work was conducted to reveal electrical tree behaviors (initiation and propagation) of silicone rubber (SIR) under an impulse voltage with high temperature. Impulse frequencies ranging from 10 Hz to 1 kHz were applied and the temperature was controlled between 30°C and 90°C. Experimental results show that tree initiation voltage decreases with increasing pulse frequency, and the descending amplitude is different in different frequency bands. As the pulse frequency increases, more frequent partial discharges occur in the channel, increasing the tree growth rate and the final shape intensity. As for temperature, the initiation voltage decreases and the tree shape becomes denser as the temperature gets higher. Based on differential scanning calorimetry results, we believe that partial segment relaxation of SIR at high temperature leads to a decrease in the initiation voltage. However, the tree growth rate decreases with increasing temperature. Carbonization deposition in the channel under high temperature was observed under microscope and proven by Raman analysis. Different tree growth models considering tree channel characteristics are proposed. It is believed that increasing the conductivity in the tree channel restrains the partial discharge, holding back the tree growth at high temperature.

Inhibition of electrical trees degradation of crosslinked polyethylene at high temperatures by electron‐buffering voltage stabilizers

“…The growth process of the electrical tree is generally divided into three stages, i.e., inception, stagnation, and re-growth stage. 24 In the inception stage, with the impact of high energy carriers and due to the formation of the low-density region, the electrical tree grows rapidly. During the stagnation stage, the space charge layer forms an independent electric field due to the space charge accumulation, weakening the effective electric field.…”

“…With the increase of the temperature, the elasticity modulus becomes lower, and the motion of the molecular chain will be further enhanced. 24 Hence, the higher temperature leads to molecular chain relaxation, reduces the mechanical strength of the material, and thus reduces its insulation properties.…”

The Development of Electrical Tree Discharge in Epoxy Resin Impregnated Paper Insulation

“…As shown in Fig. 3, the PD platform is composed of a power frequency high voltage test control system, a PD detection system and an image real-time observation system [15]. The power frequency high voltage test control system adopts YDTW-10/100 oil-immersed non-halo test transformer, which is at the rated operating voltage.…”

Space charge behaviors in cable insulation under a direct current‐superimposed pulsed electric field

“…Moreover, the electrical tree grows with the variation in the voltage amplitude but does not grow at constant voltage [13]. This experimental phenomenon was attributed to the dynamic behaviour of the space charges, that is, the space charges are trapped and detrapped under the impact of pulsed voltage while the energy released during these processes degrades the microstructure of the insulator [14], leading to breakdown.…”