基于外半导电层注入的全尺寸电缆用脉冲电声法空间电荷测量技术

发布时间：2018-04-09 11:12

本文选题：同轴电缆　切入点：空间电荷　出处：《高电压技术》2017年05期

【摘要】：高压交联聚乙烯电缆是直流输电的关键装备,但直流电场下电缆绝缘中的空间电荷积聚效应导致绝缘内电场严重畸变,直接影响电缆长期运行可靠性,因此对全尺寸长电缆空间电荷特性的实时测量显得尤为重要。基于脉冲电声(PEA)法空间电荷测量技术,根据待测电缆绝缘厚度,合理选择脉冲宽度幅值及压电传感器厚度;采用电缆外半导电层注入脉冲技术实现了高电压、长电缆下空间电荷的测量;同时分析了同轴电缆中的声波传输特点及波形矫正方法。结果表明:半导电层注入脉冲方式是测量高电压、长电缆下空间电荷特性最简单有效的办法,但脉冲沿外半导电层的分压作用会导致脉冲幅值衰减;测量系统的精度和分辨率可通过合理选择脉冲宽度幅值及压电传感器厚度而实现;另外,该系统中采用示波器对地隔离,电脑与示波器间引入数字光纤隔离技术,有效避免了传统模拟光纤对测量波形频带的限制。
[Abstract]:HV XLPE cable is the key equipment of HVDC transmission, but the accumulation effect of space charge in the insulation of DC electric field leads to serious distortion of the electric field in the insulation, which directly affects the long-term reliability of the cable.Therefore, it is very important to measure the space charge characteristics of long cable in real time.Based on the space charge measurement technique of pulse electroacoustic beam (PEAA) method, the amplitude of pulse width and the thickness of piezoelectric sensor are reasonably selected according to the insulation thickness of the cable to be measured, and the high voltage is realized by injecting pulse technology into the outer semi-conductive layer of the cable.The measurement of space charge under long cable, the characteristics of acoustic wave transmission in coaxial cable and the method of waveform correction are also analyzed.The results show that the semiconductive layer injection pulse is the simplest and most effective way to measure the space charge characteristics under the high voltage and long cable, but the pulse amplitude will be attenuated by the partial voltage of the pulse along the outer semiconductive layer.The precision and resolution of the measurement system can be realized by reasonably selecting the amplitude of pulse width and the thickness of piezoelectric sensor. In addition, the system uses oscilloscope to isolate the ground, and the digital optical fiber isolation technology is introduced between computer and oscilloscope.The limitation of traditional analog fiber on the frequency band of measurement waveform is effectively avoided.
【作者单位】：西安交通大学电力设备电气绝缘国家重点实验室;南方电网科学研究院;
【基金】：国家自然科学基金(51377131)~~
【分类号】：TM247;TM75

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