Hz超低频余弦方波极性转换电路的设计.DOCVIP

极性转换电路在XLPE电缆超低频 耐压试验中的优化设计 张晓龙，罗欣沂，唐世虎，易亚元 （西南交通大学电气工程学院，成都，610031） 摘要：0.1 Hz超低频余弦方波耐压系统，由于与工频耐压系统有良好的等效性且具备体积小，重量轻，能有效的检测出交联聚乙烯电力电缆（简称XLPE电力电缆）的绝缘缺陷等优点，在XLPE电力电缆耐压试验的应用越来越多。但现有超低频设备的极性转换电路设计有二阶阻尼震荡，造成能量损失，使得极性转换后正负电压不一致；由于XLPE电缆的特殊空间结构，这样会增加XLPE电力电缆的空间电荷积累量，最终对电缆造成隐性伤害。针对以上问题，本文提出了采用反向可馈电的极性转换电路的设计方法来解决此问题。通过Matlab/Simulink仿真表明：此方法能够补充极性转换过程的能量损失，使得极性转换后正负电压一致；仿真结果与理论分析一致，验证了设计的正确性。 关键词：反向馈电；超低频；XLPE电缆；极性转换；电荷积累 中图分类号：TM835 文献标识码： 文章编号：1001–1390（2016）00–0000–00 　　 The optimum design of polarity switch circuit in ultralow frequency withstand voltage test with XLPE cable Zhang Xiaolong, Luo Xinyi, Tang Shihu, Zhou Xinzhi, Yi Yayuan School of Electrical Engineering, Southwest Jiaotong University, Chengdu 6l003l, China) Abstract: The 0.1Hz VLF cosine square-wave puncture test system, owing to have good equivalence with the system of power frequency withstand voltage and have small size, light weight, etc., can effectively detect the deficiency of XLPE insulated power cables, and applies more and more in the withstand voltage test. But now, polarity switching circuit of ultra-low frequency device is designed with second order damped shocks with energy loss, resulting in inconsistent positive and negative polarity voltage. That will lead to the accumulation of space charge of XLPE power cable, thus making the whole performance of the system decreases. To solve the above problem, this paper proposes to make use of reverse feedback in polarity switching circuit to solve this problem. The Matlab/Simulink simulation shows that this method can complement the loss of polarity energy, making positive and negative polarity of the voltage reach agreement. Simulation results and theoretical analysis of the design are the same. Keywords: feedback, ultra-low frequency, XLPE cable, polarity switch, charge accumulation 0 引 言 近年来，随着我国电力行业的高速发展，大量电力电缆被用于城市电网改造工程，这是城市电网的主要发展趋势[1]。其中XLPE电力电缆是城市电网改造工程中使用最广泛的电力电缆[2]。由于XLPE电缆在电网中的大量使用，所以XLPE电缆的安全稳定运行和电网的安全运行息息相关。但是，随着对