【作者】 田驰；

【导师】 林莘；

【作者基本信息】 沈阳工业大学 ， 高电压与绝缘技术， 2009， 硕士

【摘要】 随着系统额定电压的升高,GIS隔离开关操作引起的快速暂态问题更加突出,而设备的雷电冲击耐受电压(LIWV)已不足以反映GIS设备的绝缘水平。因此,超、特高压GIS绝缘设计时,必须考虑VFTO的影响。本文从GIS本体结构出发,针对不同电压等级设备各自特点,建立相应的内部结构细化模型。通过借鉴本课题组三维电场分析结果,在获得GIS元件较准确计算参数的基础上,分别以湖南长沙550kV GIS抽水蓄能电站和西北地区兰州东二期800kVGIS扩建工程为研究对象,对每种运行工况下GIS隔离开关操作引起的VFTO进行数值仿真。根据计算所得大量数据,对比分析不同电压等级GIS中的快速暂态过程,探讨各关键设备处VFTO波形的变化趋势,并结合百万伏交流试验示范工程技术参数,进一步研究超、特高压GIS结构参数对VFTO幅频特性的影响。从GIS内部、外部及主变多角度分析不同部件对VFTO的影响程度,在此基础上提出有针对性地建立仿真模型及选取计算参数的侧重点。其次,对VFTO高频瞬态场引起的GIS外壳暂态电压、对二次设备的干扰电压进行分析。由于外壳暂态电压TEV峰值在数十千伏范围内变化,远小于VFTO幅值,不足以影响GIS内部暂态过程,因此VFTO仿真计算时只需考虑GIS母线芯线上的传播过程。但是,VFTO在电容式电压互感器二次电缆处引起的干扰电压的幅值和频率均较高,可能影响在线检测及二次保护系统,需要引起足够的重视。最后,对某550kV GIS隔离开关触头间隙长期燃弧的故障进行分析。建立VFTO作用下双断口断路器内部结构细化模型,首次对作用在主、辅断口的过电压幅值及均压电容器的热容量问题进行探讨。更多还原

【Abstract】 With the improvement of rated voltage in power system, the ratio of the lightning impulse withstand voltage (LIWV) to the rated voltage is decreasing, which makes the problem of fast transient phenomenon in GIS more and more obvious and serious. Thus, the influence of VFTO must be taken into consideration in insulation designing of GIS.In this paper, the calculation results of very fast transient over-voltage for operations of disconnector based on 550kV GIS of Hydro-energy storage station and 800kV GIS of LanZhoudong station are presented, using EMTP and FORTRAN. Firstly, the refining models of components in GIS are set up according to the internal structures and characteristics of different equipments, and the equivalent parameters are obtained on the basis of the analysis on three dimensional electricfield, which make sure that calculation may be more accurate and valuable. According to the calculation data, the amplitudes and frequencies of VFTO occurred on different components in 550kV and 800kV GIS are compared, and the effects of EHV and UHV GIS structure on VFTO are also presented, which will provide reference to 1100kV GIS alternating current testing demonstration engineering. By analyzed variations of VFTO occurred on components in GIS and power transformer, the refining models and calculation parameters can be set up and chosen effectively.Secondly, transient enclosure voltage and interference voltage accompany VFTO in such high frequency transient field are also studied in this paper. Transient enclosure voltage (TEV) varies in the range of several tens kilovolt, which is much lower than the amplitude of VFTO. Therefore, it is no need to consider TEV in simulation of VFTO propagation. But the interference voltage occur on the secondary cable should be paid more attention because of the high amplitude and frequency, or the on-line monitoring and secondary protection system maybe destroyed.Finally, a fault of long-term persistent arcing in 550kV GIS is analyzed base on a refining model of double-break current breaker. The over voltage occurred on the main and auxiliary contacts of breaker is calculated and the problem of thermal capacity of the equalizing capacitor is discussed for the first time.更多还原