陷阱理论在聚丙烯电老化试验中的证实

以聚丙烯薄膜为试样，在真空中进行了工频电老化试验，在电老化过程中，同时测量试样的剩余击穿场强和表面电位增量，并在不同电压下测量了寿命时间，实验发现在广泛的电压范围内，在双对数坐标上，试样的的寿命曲线，剩余击穿场和表面电位增量都是折线，且具有相关性，证实了陷阱在介质击穿过程中的决定性作用和寿命的理论公式中幂指数随电场强度范围的不同而变化的理论预言。不管电老化电压如何，试样的击穿都发生在陷阱密度，自由

VERIFICATION OF THE TRAP THEORY OF POLYMER BREAKDOWN BY ELECTRICAL AGEING IN PP

The a c ageing of polyprophlene in vacuum is investigated in this paper. The residual breakdown strength and the increment of the surface potential of samples are measured at the same time during the ageing. The life of samples under different ageing voltages are measured. It is shown from experiments that the life curve of sample, residual breakdown strength and the increment of the surface potential are broken line, and are interrelated to each other in double logarithmic coordinates in wide scope of votlage. The predictions are proved that trap plays a determinant role in the breakdown, and the life power in theoritical formula varies with electrical strength.No matter how the electrical ageing voltage change, the breakdowns of all the samples take place when the trap density, the free radicals reach a certain value. It is confirmed that the critical value of trap density should be taken as the breakdown condition in theoretical deduction.