摘要
油中电弧产生的陡强压力波是导致变压器燃爆事故的直接原因,研究变压器油中压力波的产生过程与传播特性对增强变压器防灾御灾能力具有重要意义。为此采用油中脉冲电弧放电法产生压力波,极大减弱工频电弧中持续产气、重燃对压力波基本过程观测的干扰,搭建了油中脉冲放电压力波光-电联合诊断平台,实验采集电压、电流和压力时序信号以及动态纹影图像,研究油中电弧放电压力波的产生过程。实验结果表明,油中压力波的产生可分为电弧膨胀和气泡脉动2个阶段:电弧通道迅速膨胀并压缩油介质,产生一系列激波,继而叠加形成高频一次压力波;放电过程中产生的气泡经历多个膨胀和坍缩循环,溃散时形成二次压力波,其压强更高、频率更低。增大电极间距,一次压力波由球面波转变为沿电极方向的柱面波,而二次压力波会因多点产生的压力波相互叠加,其波前厚度显著增大。实验数据拟合得到油中压力波衰减系数为1.2~1.4,显著高于水中的衰减系数。
The steep and intense pressure waves generated by the arc in oil is the direct cause of transformer tank explosions and subsequent fires.Understanding the generation and propagation characteristics of these pressure waves in transformer oil is crucial for improving disaster prevention measures.This study employs a pulsed arc discharge method in oil to generate pressure waves,significantly reducing the interference from continuous gas production and reignition observed in power frequency arc experiments.An integrated optical-electrical diagnostic platform was constructed to collect signals of voltage,current,and pressure time series and dynamic schlieren images,so as to analyze the pressure wave generation in oil.The experimental results reveal that the generation of pressure waves in oil can be divided into two stages:arc expansion and bubble pulsation.In the microsecond time scale,the arc channel rapidly expands and compresses the oil medium,generating a series of shock waves that superimpose to form a high-frequency primary pressure wave.During the discharge process,the generated bubbles undergo multiple cycles of expansion and collapse,forming secondary pressure waves upon collapse,characterized by higher pressure and lower frequency.Increasing the electrode spacing transforms the primary pressure wave from a spherical wave to a cylindrical wave along the electrode direction.Furthermore,the non-uniform pressure distribution and the influence of the electrode structure lead to significant wavefront thickness due to the superposition of secondary pressure waves generated at multiple points.Experimental data fitting indicates that the attenuation coefficient of pressure waves in oil is approximately 1.2~1.4,significantly higher than the attenuation coefficient in water.This suggests a faster attenuation rate of pressure waves in oil due to viscous loss,thermal conduction,and energy dispersion.
作者
李元
王亚桢
施沛澍
袁磊
石亚轩
张冠军
LI Yuan;WANG Yazhen;SHI Peishu;YUAN Lei;SHI Yaxuan;ZHANG Guanjun(School of Electrical Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2024年第10期4349-4357,共9页
High Voltage Engineering
基金
国家重点研发计划(2023YFB2407000)。
关键词
变压器油
脉冲电弧放电
压力波
产压机理
传播特性
transformer oil
pulsed arc discharge
pressure wave
pressure generation mechanism
attenuation characteristics
