Thermally stimulated electrical measurement of an LDPE film stressed under a nonuniform electric field: influence of the space charge on treeing

The authors measured the TSC (thermally stimulated current) and TSSP (thermally stimulated surface potential) on low-density polyethylene (LDPE) films sandwiched between needle electrodes and plane electrodes, and then evaluated the space charges. To confirm that injection occurs from needle electrodes and that injection space charges are trapped around the needle tips, the experiments were carried out with different numbers of needle electrodes, e.g. 20. Finally, the authors examined the influence of the space charges on the mechanisms of treeing in an LDPE film by measuring the inception voltage of treeing in the film