【作者】 颜湘莲；

【导师】 陈维江；

【作者基本信息】 中国电力科学研究院 ， 高电压与绝缘技术， 2009， 博士

【摘要】 随着输电系统电压等级的提高和特高压输电工程的建设,交流输电线路单相接地潜供电弧自熄特性问题日渐突显,对确保系统单相重合闸成功率具有重要意义。现有研究对潜供电弧这种处于开放环境中的长间隙小电流空气电弧的物理特性涉及甚少,本文在大量电弧试验基础上,建立了输电线路潜供电弧仿真模型,计算潜供电弧自熄特性,为确定系统单相重合闸整定时间提供指导。从模拟试验角度出发,设计了10kV试验回路,进行了长间隙小电流燃弧试验,结合国家电网公司特高压交流输电工程关键技术研究潜供电流自熄特性的项目,进行了特高压输电线路潜供电弧自熄的模拟试验。测量了电弧试验波形,拍摄了电弧的动态图像,阐明了电弧电压和电流波形的发展轨迹,给出了电弧的弧道电阻和动态伏安曲线,揭示了电弧自熄的弧阻特征。对燃弧时间与电流、恢复电压梯度和风的关系进行了统计分析,结果表明风对电弧自熄的影响显著。根据空气电弧等离子体辐射的光谱诊断原理,结合彩色CCD的光谱响应特性,由经光学预处理的彩色CCD高速图像采集系统拍摄长间隙空气电弧图像,采用数字图像处理技术分析电弧彩色位图文件,通过阿贝尔变换得到电弧径向光强分布,用比色方法计算电弧温度。设计并研制了长间隙空气电弧温度测量系统,对小电流电弧温度特性进行了测量和分析,为研究潜供电弧自熄特性提供了参考和依据。基于传统电弧理论和试验研究结果,采用非线性时变电阻描述弧道特性,区别短路电弧与潜供电弧的特性差异,建立弧道电阻动态方程,分析潜供电弧的运动特性,获得电弧实时长度以迭代计算弧阻,结合潜供电流零休时间较长的特点,根据能量守恒原则提出了判断电弧是否熄灭的弧阻判据,给出了计算潜供电弧特性的等效电路和仿真流程,建立了潜供电弧仿真模型。编制了实用程序,对10kV试验回路产生的小电流电弧和特高压输电线路潜供电弧模拟试验的电弧电流、电压、弧阻和燃弧时间等特性进行了仿真计算,与试验结果基本一致。本文研究电弧长度的实时变化和电弧自熄的弧阻特性,提出了一种计算输电线路潜供电弧自熄特性的仿真模型。结合我国特高压交流试验示范工程,运用本文建立的潜供电弧仿真模型,对电弧的运动特性、电流波形等进行了仿真计算,得到了潜供电弧自熄时间。在特高压交流试验示范工程进行的人工单相短路接地试验表明,仿真结果与现场的实测结果基本吻合,验证了输电线路潜供电弧仿真模型的正确性和有效性。上述研究成果表明,本文提出的潜供电弧模拟试验方法合理、结论可信,潜供电弧温度测量系统可有效获得电弧等离子体温度特性,试验结果对分析电弧自熄特性和建立潜供电弧仿真模型具有参考价值,文中建立的潜供电弧仿真模型用于分析潜供电弧自熄特性是可行的,可直接计算潜供电弧自熄时间,具有工程实用价值。更多还原

【Abstract】 With the increase of the voltage degree and the construction of UHV transmission project, it is important to investigate the self-extinction behavior of secondary arc in AC transmission line for guaranteeing the successful working of sing-phase re-closure device in power system. As will be readily seen, the physical characters of secondary arc have been little involved in the common research. On the basis of arcing tests, the simulation model of secondary arc in transmission line was established in this paper to compute the self-extinction behavior of secondary arc, providing the theoretical foundation for setting time of sing-phase re-closure.From the simulated test point of view, the test circuit of lOkV for arc at low current was designed, and experimental works associated with arc were operated. As the project was founded to study the secondary current in the UHVAC transmission line by State Grid Corporation of China (SGCC), a great amount of simulated tests on the self-extinction behavior of secondary arc were conducted at Shahe Laboratory of NorthChina Electric Power Research Institute (NCEPRI)) combined with China Electric Power Research Institute (CEPRI). The arc waveforms of voltage and current were recorded and arcs’developing films were taken by the high-speed imaging system. Arcs’physical characteristics were presented to get their time-varying characters. The transitional traces of arc waveforms were discussed with the physics doctrine. Arc resistance curve and its dynamic u-i characteristics were interpreted through the energy balance principle at the time of arc self-extinction. Finally the relations of the duration times of arc to current, voltage gradient and wind speed were studied statically to exhibit that wind is one of the key factors for arc self-extinction. All works have set the basis for arcing tests of secondary arc.According to the spectrum diagnosis principle for plasma radiation of air arc, combined with the spectrum response characteristics, the arc films in long gap were taken by the corrected high-speed image sampling system with the color CCD camera added the interference filters, with the numerical image process technology, the pixels at character wavelengths were reverted to the radiation strength. And then the radial distribution of arc radiation was gotten by Abel transform. The temperatures of arc plasma were calculated by the colorimetric method of the relative radiation strength. The temperature measurement system was developed for air arc in long gap in the paper for the first time, and the temperature distributions of arc were measured in the gross and discussed primarily. The measured results on the temperature characteristics have provided the reference for analyzing the self-extinction behavior of secondary arc.Based on Mayr arc theory, one of the classical arc theories, a non-linear time-varying resistance was used to descript the arc channel condition, with the influence on the self-extinction behavior of secondary arc by the short-circuit current, taking account of the movement characters of secondary arc in transmission line, so the real-time arc length of secondary arc was gotten to compute arc resistance in iteration. The criterion associated with arc resistance was proposed to judge arc self-extinction on the energy balance principle. The equivalent circuit connected with the applied system was also put forward to calculate arc characteristics, and the simulation flow for arc self-extinction behavior was further expressed in detail. The simulation model of secondary arc was established. The relevant program was edited for simulation. The waveforms of arc voltage, current, resistance and the duration times of arc were calculated for the test circuit of lOkV and the simulated tests of secondary arc in UHV transmission line, conforming to the corresponding test results. The simulation model for secondary arc in transmission line keeps one-up advantage over the world on simulating secondary arc to get its self-extinction behavior, where the elongation of arc length and the characteristics of arc resistance at arc self-extinction were taken into account for the application of sing-phase re-closure.The UHVAC demonstration project in China was set as an example, arc movement, arc current and voltage waveforms, and the duration times of secondary arc were computed by the simulation model proposed in the paper. Compared with the results from the artificial single-phase grounding tests in the demonstration project, the simulation results conform to the measured data, which proves the accuracy and the effectiveness of the simulation model.All the achievements have shown that, the test methods and conclusions are reliable, and the temperature measurement method for arc plasma is valid, providing the important reference to further investigate and simulate secondary arc. And the simulation model proposed in the paper is available and feasible for secondary arc in AC transmission line, which can be used to compute arc characteristics and attain the duration times of secondary arc directly, being of great engineering application.更多还原