Frequency Dependence of Electroluminescence and Dissipation Current Waveform in LDPE film

Polyethylene (PE) is widely used as an insulating material for power cable. The simultaneous observation system for electroluminescence (EL) and dissipation current waveform of polymeric film has been developed by authors. By using this system, the simultaneous observations in low-density polyethylene (LDPE) film were carried out at 50, 100 and 200 Hz, respectively. The frequency dependence of the inception level of EL and the 3rd harmonic components, which has been estimated from the results of the electric field dependences of EL and the dissipation current, was relatively small. On the other hand, the estimated relaxation time from the results of the time dependences of EL and the dissipation current, which has been carried out just after the electric field dependence at each frequency, seems to be in inverse proportion to the applied frequency. It seems to be considered that the duration time of EL at each frequency will depend on the number of polarity reversal under AC high field.