低频交流电压下低密度聚乙烯的空间电荷特性  

Space Charge Characteristics of Low-density Polyethylene at Low-frequency AC Voltages

作　　者：魏鼎欣 刘鹏[1] 谢宗良 庞曦 许天蕾 彭宗仁[1] WEI Dingxin;LIU Peng;XIE Zongliang;PANG Xi;XU Tianlei;PENG Zongren(State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学电工材料电气绝缘全国重点实验室,西安710049

出　　处：《高电压技术》2024年第5期1997-2008,I0013,共13页High Voltage Engineering

基　　金：国家自然科学基金(U23B20132)。

摘　　要：分频输电技术已逐步成为实现碳中和及海上风电远距离传输的主流方案之一。然而,对高压分频输电背景下的电气设备研究较为欠缺,在频率改变对电缆绝缘材料特性影响方面尚需深入研究。为此,采用具备快速检测能力的脉冲电声测试系统,研究了低密度聚乙烯材料在分频电压下不同电场强度、温度时的空间电荷特性以及频率改变对电荷积聚行为的影响。结果表明:当场强及温度条件较为苛刻时,电荷积聚明显;而随着频率的降低电荷积聚量增加,频率下降至20 Hz后,电荷增长速度显著提高。在此基础上,建立了应用于交变电场下的双极型载流子模型,通过仿真计算对实验观察进行了合理化解释,揭示了电场、温度及频率对空间电荷行为的影响机理。研究方法和结果可为海上风电分频输电系统中的频率选择及线缆绝缘优化设计提供理论支撑。Fractional frequency transmission technology has gradually become one of the mainstream solutions for realizing carbon neutrality and long-distance transmission of offshore wind power.However,the research on electrical equipment in the context of high-voltage FFTS is rarely available,and the effects of frequency change on the characteristics of cable insulation materials need to be studied in depth.To this end,a pulsed electroacoustic test system capable of rapid detection was used to investigate the space charge characteristics of low-density polyethylene materials at crossover voltages with different field strengths and temperatures as well as the effect of frequency change on the charge build-up behavior.The results show that the charge accumulation is obvious when the field strength and temperature conditions are more severe;while the charge accumulation becomes more remarkable with the decrease of frequency,and the charge growth rate increases significantly when the frequency decreases below 20 Hz.Based on this,a bipolar carrier model applied under alternating electric field was developed,and the experimental observations were rationalized by simulation calculations to reveal the mechanism of the influence of electric field,temperature and frequency on the space charge behavior.The research methodology and results can provide theoretical supports for the frequency choice and optimal design of cable insulation in frequency-divided transmission systems.

关 键 词：碳中和 海上风电 分频输电 低密度聚乙烯 空间电荷 电场分布 

分 类 号：TM614[电气工程—电力系统及自动化]