High-Field Conduction and Electrical Breakdown of Polyethylene at High Temperatures

Abstract

The mechanism of the breakdown occurring when a dc ramp voltage is applied to low-density polyethylene (LDPE) and silane cross-linked PE at high temperatures is discussed, using experimental results on the Young's modulus Y, high-field conduction and pre-breakdown currents. The electric strength F B of PE was found to be a function of Y, irrespective of cross-linking. It was also found that, over a wide temperature range, a sharp pre-breakdown current increase could not be detected till a time before breakdown of 100 ns, the resolution limit of the measuring system. The results showed that, under the present experimental conditions, thermal breakdown is not applicable to PE over a wide temperature range and that breakdown is initiated by an electronic process which has a very short time lag to breakdown of the order of some tens of ns or less.

Filled liquid silicone rubbers: possibilities and challenges

“…[20] In Figure 2 the breakdown strength as function of Y is plotted. The results indicate that the resistance of the elastomers to dielectric breakdown is indeed enhanced with the increase of Y but not in a trivial or universal way.…”

A consideration of potentials of low‐density polyethylene using metallocene catalyst as insulator for power cable

“…The conduction current was measured with a 1-Mohm detecting resistor connected in series with the lower electrode, and recorded by an electrometer. The detailed electrode shape was described in our previous papers [7,8].…”

Electromechanical instabilities of thermoplastics: Theory and in situ observation

“…The critical electric field for the instabilities scales with square root of yield stress of the thermoplastic and depends on its Young's modulus and hardening property. Thermoplastics have been used as dielectrics in diverse areas ranging from insulating cables, [1][2][3][4][5] polymer capacitors [6][7][8][9] to polymer actuators 10 and energy harvesters. 11 Many applications 1,12,13 require thermoplastics to sustain high voltages as well as high working temperatures.…”

“…(2) Existing theoretical models for electromechanical instabilities of thermoplastics generally assume the polymers to be mechanically unconstrained. However, thermoplastics are usually constrained by electrodes in practical applications, such as in insulating cables [1][2][3][4][5] and polymer capacitors. [6][7][8][9] As a result, the importance or even existence of electromechanical instabilities in thermoplastics has been undergoing debate over decades.…”