【作者】 孙秋芹；

【导师】 李庆民；

【作者基本信息】 山东大学 ， 高电压与绝缘技术， 2012， 博士

【摘要】 为提高系统稳定性和供电可靠性,单相重合闸技术在超／特高压线路上获得广泛应用。特高压线路较长,运行电压高,潜供电弧的熄灭是一个技术难题。如果潜供电弧不能及时熄灭,将使断路器重合于弧光接地故障,造成重合闸失败。研究潜供电弧的产生机理与动态物理特性,进而发展有效的抑制技术,具有重要的理论意义和应用价值。本文结合我国在建的特高压输电工程实践,针对潜供电弧的物理特性与抑制技术开展探索与创新研究。通过建立潜供电弧的低压模拟实验平台,研究潜供电弧的动态物理特性与数学建模方法,完善潜供电弧熄灭、重燃机理的分析方法,发展新型的潜供电弧抑制技术。低压模拟实验是研究潜供电弧物理特性的重要技术途径。本文完善了潜供电弧实验回路及其测量系统,建立了特高压线路潜供电弧的低压物理模拟实验平台,通过观测长间隙潜供电弧的运功图像和物理参量,揭示潜供电弧弧根与弧柱的运动特性及其对电弧电流及电压的影响规律,获得了潜供电弧熄灭与重燃的动态物理特征。本文还就特高压半波长输电线路潜供电弧的物理特性开展了探索研究,建立了新的潜供电弧实验回路拓扑,重点分析潜供电弧的燃弧时间特性与伏安特性等。通过大量实验揭示了风对半波长线路潜供电弧的影响机制,并获得了两个燃弧时间临界点,可作为半波长输电线路快速接地开关配置的参考依据。潜供电弧零休阶段的物理特性是影响电弧熄灭与重燃的关键所在,此时弧道恢复电压上升率是反映潜供电弧熄灭与重燃机制的重要参数。本文将单相接地故障过程分解为4个阶段,基于建立的复频域等效模型研究获得了潜供电弧弧道恢复电压上升率的影响因素及其作用规律。该研究结果进一步完善了潜供电弧熄灭与重燃机理的分析方法,可为特高压输电线路的参数优化以及重合闸策略提供理论基础。特高压输电线路并联电抗器的配置是一个多目标统筹问题。本文基于建立的输电线路分布参数耦合模型以及潜供电弧动态模型,纳入三种特高压输电线路潜供电弧的实验参数进行计算与比较,获得面向潜供电弧抑制的并联电抗器和中性点小电抗优化取值准则。同时,兼顾线路非全相运行以及谐振过电压抑制,基于谐振频率分析法,提出临界谐振高抗的概念并给出了相应的计算公式,可用于并联电抗器与中性点小电抗的进一步优化。考虑到现有潜供电弧抑制措施的不足,本文研究提出一种基于断路器并联阻抗的新型潜供电弧抑制技术,适用于超／特高压等级输电线路。大量分析表明,采用该抑制拓扑可将潜供电流与弧道恢复电压的强制分量减小至极低水平,从而显著加速潜供电弧的熄灭。该抑制技术可作为现有潜供电弧抑制措施的一种有效补充,但尚待实用化研究。本文工作成果进一步丰富了输电线路潜供电弧研究的基础理论和分析方法,对特高压输电技术领域的科学研究与工程设计具有重要意义。更多还原

【Abstract】 Single-phase auto-reclosure (SPAR) is widely used in extra high voltage (EHV) and ultra high voltage (UHV) transmission lines to improve the stability and reliability of the power systems. Reliable extinction of the secondary arcs is a critical issue for the UHV transmission lines, otherwise, the circuit breaker would be re-closed at grounded arc faults, may will result in failure of the re-closing operation. Hence, investigation on the formation mechanism and physical characteristics of the secondary arcs, as well as development of effective suppressing technologies, are of great significance in both theory and application arenas.Based on the ongoing UHV transmission project in China, secondary arc physics and corresponding suppressing technologies are systematically researched in this dissertation. The research contents cover several aspects as follows, namely establishment of the test platform for physical simulation of the secondary arcs, physical and mathematical modeling methodology of the secondary arcs incorporating the extinction and re-ignition mechanisms, development of novel suppressing technologies of secondary arcs and so on.Low voltage physical simulation is an effective approach to study secondary arcs. Based on an established experimental system, high speed images as well as the arc current and voltage waveforms are recorded as to explore the unique and intrinsic mechanisms of the secondary arc inception, development, movement, extinction and re-ignition. The motion characteristics of the arc root and arc column as well as their impacts on arc current and voltage are also fully elucidated and illustrated through the high-speed imaging equipment.Specifically for the secondary arcs of half-wavelength transmission lines (HWTL), exploratory research are also carried out, for which a new test topology is proposed via Thevenin transform of the established equivalent circuitry. With physical experiments, two critical points of the arcing time are obtained as to present useful reference for optimization of the high speed grounding switch (HSGS) arrangement along HWTL. Further, wind impacts on the secondary arc physics are given full account through large numbers of experiments.Secondary arc physics during zero-crossing stage of arc current plays a unique role to determine the arc extinction and re-ignition mechanisms, where the rate of rise of the recovery voltage (RRRV) across the arc path is one of the most important parameters to influence secondary arc extinction. The whole process of a single-phase-to-ground fault are divided into four stages, based on which corresponding equivalent circuit of the transmission lines is established in the complex frequency domain. The impact factors and their interacting mechanisms on the RRRV of secondary arc path are studied in details. The research results present theoretical basis for parameter optimization and auto-reclosing strategy development of the UHV transmission lines.The parameter determination of the four-legged shunt reactors within UHV transmission lines is a multi-objective issue of optimization. With a dynamic secondary arc model being taken into account, the impacts of the initial arc length and the neutral reactor on the arcing time of the secondary arcs are studied as to set up a guide criterion for parameter optimization of the four-legged shunt reactors. In addition, with full consideration of secondary arc suppression as well as resonant over-voltage mitigation due to out-of-phase operations, further optimization methodologies are presented for the four-legged shunt reactors.To achieve preferable suppression of the secondary arcs, a novel scheme based on paralleled impedance to line circuit breaker is proposed, which is applicable to both EHV and UHV transmission lines. An algorithm for topology parameter design and optimization under different conditions is given based on equivalent circuit transform. Simulation results indicate that the proposed arc suppressing theme can greatly reduce the forced components of the secondary arc current and the recovery voltage, thus resulting in quick extinction of the secondary arcs. The proposed scheme may be an applicable alternative and supplement of the traditional secondary arc suppressing measures prevailing within EHV and UHV transmission lines.The research work in the dissertation presents further development in both fundamental theories and analyzing methodologies for secondary arc study, and is of great significance for future development of the UHV transmission technologies.更多还原