Time behavior of gas pressure and PD activity in insulation cavities under AC voltage

Abstract

In the framework of developing defect-based life models (i.e. the life model of partial discharge-induced damage growth from a micro-void in polymer matrix), ageing tests were performed on PE layered specimens with artificial cavities under constant gas pressure and constant gas volume conditions, respectively. Time behavior of the discharge repetition rate and amplitude were recorded and compared under these two conditions. Results show that pressure variation has little influence on PD activities at constant gas volume. Under constant gas pressure, the evolution of gas volume has similar characteristic to the product of discharge amplitude and repetition rate.

Temperature‐dependent effect of gas pressure on electrical tree in XLPE cable

“…However, once the electrical trees occur in the insulation of XLPE cable, they will develop rapidly and even lead to failure when the channels meet to the opposite electrode. In recent decades, the factors of initiating and propagating the electrical trees in polymer have caused much attention [1][2][3][4][5][6][7][8][9][10][11].…”

“…In some special occasions, gas-filled spaces will exist in XLPE cable insulation such as insulation thermal corrosion or internal discharge [6]. The variation of gas pressure inside insulation is related to the change of temperature and the occurrence of the fault gas, which seriously affects the development of the electrical tree [8]. To further clarify the effect of temperature on XLPE insulation, a systematic study regarding the influence of gas pressure on electrical treeing behaviour and partial discharge (PD) characteristics under different temperature is very important, and the impacting mechanism should be analysed in detail.…”