Space charge accumulation and breakdown in LDPE and LDPE/MgO nano-composite under high dc stress at various temperatures

The relationship between space charge accumulation and breakdown at various temperatures is investigated by observing the space charge formation in low density polyethylene (LDPE) and LDPE/MgO nanocomposite material under dc high stress. We have reported, earlier, that, enhancement of electric field in LDPE by packet-like charge under dc stress might be a cause of its electrical breakdown. Furthermore, it has been found that such enhancement does not take place in LDPE/MgO nanocomposite under the same conditions. Therefore, it is believed that the addition of MgO to LDPE results in suppression of charge injection. To understand the effect of temperature, we tried to observe the charge accumulation under high dc stress at various higher temperatures. This is reported in this paper. It is seen that the packet like charge, in LDPE, plays an important role on the electric breakdown at higher temperature. On the other hand, the suppression effect of charge injection by MgO nano filler is still working well even at higher temperatures.