纤维素颗粒物对变压器油冲击击穿特性影响的试验研究

Experimental Study of Cellulose Particles Effect on Impulse Breakdown in Transformer Oil

针对不同纤维素颗粒物含量的变压器油进行冲击击穿试验研究。应用球盖形电极模拟油中稍不均匀电场,采用波形参数分别为1.4/50μs、14/220μs、80/850μs和240/2400μs的四种冲击电压对低、中、高三种不同纤维素颗粒度水平的变压器油进行冲击击穿试验。试验结果的统计分析显示,冲击电压波形和纤维素颗粒度水平均对变压器油的击穿电压产生影响,更长的波形持续时间或更高的纤维素颗粒度水平均导致冲击击穿电压的降低。特别是高颗粒度水平油样在80/850μs和240/2400μs的冲击电压下的U50%下降显著。通过对纤维素颗粒在1.4/50μs和240/2400μs冲击电压下的运动观测发现,240/2400μs冲击电压可促进纤维素颗粒物在电极间强场区的聚集,导致油间隙击穿电压的进一步降低。

This paper conducts an experimental research about the effect of cellulose particles on impulse breakdown in transformer oil.The hemispherical electrodes immersed in the bulk of the transformer oil are used to form a quasi-uniform electric field.The breakdown tests are carried out and the breakdown voltages for three cellulose contamination levels oil under four kinds of impulse,1.4/50μs,14/220μs,80/850μs and 250/2600μs,are obtained.The results show that both the impulse waveshape and cellulose contamination level exert an effect on the breakdown voltage of transformer oil.Specifically,longer impulse duration or higher cellulose contamination levels of transformer oil lead to the decrease of impulse breakdown voltage.It is noted that the effect of the high level cellulose contamination for U50%becomes much more significant under the impulses of 80/850μs and 240/2400μs.Another relevant experiment is finally conducted under the impulses of 1.4/50μs and 240/2400μs on cellulose particles motion in transformer oil gap submitted to a divergent electric field,and the suspension and aggregation of cellulose particles are observed under the impulses of 240/2400μs.It is concluded that the particle can play a catalytic role in the impulse breakdown of the oil gap.