非标准雷电冲击电压下油纸绝缘击穿特性

发布时间：2018-01-06 00:33

本文关键词：非标准雷电冲击电压下油纸绝缘击穿特性　出处：《高电压技术》2014年09期 　论文类型：期刊论文

【摘要】：变压器实际遭受的雷电冲击电压的波前时间及持续时间变化范围很大,传播过程中的折反射还会造成雷电波的波形振荡。雷电侵入变压器绕组后会引起内部谐振,在匝间和饼间形成较高电位梯度,从而导致匝间和饼间的击穿事故。因此设计了油-隔板和匝间绝缘模型,研究了冲击电压波前时间、振荡频率对绝缘模型击穿特性的影响。结果表明:2种绝缘模型击穿电压均随波前时间的降低而增加,波前时间0.25μs陡前沿冲击电压下的U50%比标准雷电冲击下提高了10%~17%;对于匝间绝缘模型,其放电时延受绝缘层厚度和波前时间的影响显著,并且放电时延对波前时间的敏感度随着纸层层数的增加而升高;匝间绝缘模型能够耐受幅值比标准雷电冲击电压幅值更高的振荡雷电冲击电压,模型的U50%击穿电压随振荡频率增大而增大,振荡频率335 kHz时的U50%是标准雷电下的1.25倍;此外,当匝间绝缘模型中绝缘纸总厚度保持恒定时,绝缘纸层数的增加提高了绝缘模型的击穿强度。
[Abstract]:The front time of lightning impulse voltage transformer actually suffered and the duration of a wide range, but also spread in the process of reflection wave oscillation caused by lightning. The lightning transformer winding will cause internal resonance, the formation of higher potential gradient in turn and the bread, which leads to the breakdown of inter turn and Inter. So the cake the design of the oil separator and interturn insulation model of impulse voltage wave front time, influence the oscillation frequency of the insulation breakdown characteristics of the model. The results show that the 2 models of insulation breakdown voltage are increased with the decrease of wavefront time, wavefront time 0.25 s a steep front impulse voltage U50% than the standard lightning impulse to improve 10%~17%; for interturn insulation model, the discharge delay is affected by the thickness of the insulating layer and the front time significantly, and discharge delay on wavefront time sensitivity with the number of layers of paper Increased; the interturn insulation model can oscillating lightning impulse voltage withstand amplitude than the standard lightning impulse voltage amplitude higher breakdown voltage, U50% model increases with the increase of oscillation frequency, oscillation frequency of 335 kHz when the U50% is 1.25 times the standard lightning; in addition, when the constant total thickness of insulation insulation paper model interturn breakdown strength, insulation model increase insulation paper layers.

【作者单位】：西安交通大学电气工程学院;中国电力科学研究院;
【分类号】：TM403
【正文快照】： 0引言统计表明,绝缘故障占110 kV及以上变压器事故的80%以上(匝间绝缘、主绝缘及套管绝缘各占约43%、23%及15%)。雷电过电压是导致电力变压器绝缘故障的重要原因。雷电冲击耐受电压是变压器绝缘设计的重要依据之一,目前雷电过电压下变压器的绝缘强度用1.2/50μs标准雷电冲击(s

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