Aging of the over-voltage protection elements caused by over-voltages

摘要

The aim of this work is examining the influence of the number of the activation ― over-voltage pulses to the aging of over-voltage protection elements. Both non-linear (gas-filled surge arresters (GFSA), varistors, over-voltage diodes) and linear (capacitors ― constituents of filters) over-voltage protection elements were tested. The instruments employed allow reliable measurements, 1000 consecutive activation were tested. The double-exponential current pulse (amplitude I_1~(max) = 13 A, I_2~(max)= 16 A, rise time T_1 = 8 μs, fall time T_2 = 20 μs) for non-linear elements and a double-exponential over-voltage pulse (rise time T_1 = 1.2 μs, fall time T_2 = 50 μs) of the amplitude U_1~(max) = 320 V, U_2~(max) = 480 V and U_3~(max) = 640 V for capacitors were used. The experimental results show that the over-voltage diodes are the most reliable elements in view of characteristic modifications that are consequence of aging. However, it was observed that varistors, GFSA and capacitors undergo noticeable changes in characteristics.