变压器绕组存在分布电感和分布电容,而分布电容大小与组间,匝间油介质的介电常数εr大小相关.在油装变压器系统中,当绝缘油质发生劣变时,将使εr増大,线圈将承受较低的谐振电压,会使低频频谱带加宽,这样容易形成多频叠加的共鸣性破坏.同时,εr増大也会引起初始极化电荷的迅速增加,在一定的电场作用下,与质点的碰撞电离几率会雪崩发生,将会引起对绕组的游离性击穿.%There is distributed inductance and capacitance in the transformer winding, and the size of the distributed capacitance is related to dielectric constant εr of the oil medium between groups and turns.In the oil transformer system, insulating oil deterioration will increase εr, and the coil will bear lower resonant voltage, thus widening the band of the low frequency spectrum, so that resonance destruction with multiple frequency superposition will likely occur.In the meantime, εr increase will also lead to rapid increase of initial polarization charge.Under certain electric field action, that will lead to avalanche of particle collision ionization probability, thus resulting in dissociated breakdown of the winding.
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