【作者】 王娜；

【导师】 林莘；

【作者基本信息】 沈阳工业大学 ， 高电压与绝缘技术， 2013， 博士

【摘要】 气体绝缘变电站（GIS）中隔离开关操作过程中会产生复杂的电磁暂态现象，电磁暂态过程一部分发生在GIS内部，产生影响GIS内部设备绝缘的快速暂态过电压（VFTO），另一部分发生在GIS壳体与大地之间，产生影响GIS二次设备正常工作的外部过电压，即暂态壳体电位升高（TEV）。随着GIS的电压等级越来越高，由VFTO和TEV所引起的绝缘问题及对二次设备的干扰问题也越来越受到人们的关注，因此，对特高压GIS中隔离开关操作引起的电磁暂态问题进行深入研究是保证变电站安全运行的重要课题，对我国特高压GIS变电站的远期建设和运行具有重要指导意义。由于受到试验和实际测量条件限制，对于VFTO和TEV的研究主要是通过计算机仿真。在VFTO和TEV仿真计算过程中，搭建完整、准确的暂态模型将在一定程度上提高暂态电压的计算准确度。本文重点从以下几个方面进行深入研究：探讨隔离开关投切电阻对VFTO幅值、频率及上升时间的影响，并详细讨论快速和慢速两种GIS隔离开关投切电阻的热容量问题，指出隔离开关是否装设投切电阻还需要综合考虑变电站实际情况、隔离开关操作速度和电阻的热容量等问题；研究隔离开关操作速度对残余电荷和重燃次数的影响，同时指出隔离开关操作速度对电弧的预击穿和燃弧时间特性产生影响。在VFTO的计算过程中，对隔离开关操作电弧的准确描述，是影响VFTO计算精度的关键因素。在分段电弧模型基础上，提出一种动态电弧模型。在预击穿阶段，该模型考虑击穿延时对VFTO的影响，采用双曲线形式的时变电阻；在熄弧阶段建立完整的麦也尔（Mayr-Schwarz）模型描述电弧的动态物理过程。结合某1100kV GIS实际电路，详细计算两种电弧模型下GIS内部的VFTO幅值、频率和陡度，同时讨论了击穿延时对VFTO波形的影响。计算结果表明：动态电弧模型下VFTO具有幅值较高、频率较高、上升陡度较大的特点；击穿延时对VFTO的初始上升时间和幅值有影响。通过VFTO仿真与实测数据相比较可知，动态电弧模型是分段电弧模型的进一步完善，对于提高VFTO仿真计算的精度有重要意义；在一次动态电弧模型基础上，从间隙击穿、电弧熄弧判据等方面进行讨论，构建一个能够反映多次重燃的GIS隔离开关电弧模型，并依据此模型对VFTO进行仿真分析。VFTO作用下MOA的暂态过程非常复杂，因此有必要对其进行深入研究。作为过电压保护的重要设备，MOA模型的准确性尤为重要，目前，MOA在VFTO下的电气模型还未达成共识。本文在分析常用MOA模型基础上，全面考虑MOA在陡波下的动态特性，建立MOA的动态暂态模型。以特高压GIS变电站为例，研究了MOA极化模型和动态暂态模型对VFTO的影响。仿真结果表明，MOA动态暂态模型下，VFTO峰值较低、高频分量稍有增加且持续时间最短，更适合于VFTO下的仿真建模。利用多导体传输线模型，建立GIS外部暂态模型，将其与GIS内部模型和考虑接地体间互感作用的暂态地网模型相结合，建立GIS整体仿真模型，详细计算分析VFTO和TEV幅值及其频谱特性，通过与实测波形对比分析，表明本文所建立的GIS整体模型使仿真结果更加接近实际，进一步提高仿真准确性。最后，详细分析影响TEV的主要因素，提出相应的抑制措施，对GIS变电站的设计和安装起到一定的指导作用。更多还原

【Abstract】 Disconnector switching operation will produce complex electromagnetic transientphenomenon in GIS, part of the electromagnetic transient process occurred in the interiorof GIS produce very fast transient overvoltage(VFTO),another part of theelectromagnetic transient process occurred external overvoltage between the GIS shelland the earth,which affect GIS secondary monitoring,measurement, protection and otherequipment work properly,that is transient enclosure voltage (TEV). GIS voltage level isgetting higher and higher, the insulation problems caused by VFTO and TEV get moreand more attention. In-depth study to the VFTO and TEV problem is an important issueto ensure the safe operation of the substation, and it has important guiding significance onUHV GIS substation forward construction and operation.Currently, limited by test and the actual experimental conditions，the primary meansof researching VFTO and TEV is computer simulation. In the process of VFTO andTEV simulation, building a complete、accurate transient model will improve transientvoltage calculation accuracy. This paper fouses on study from the following aspects:Discussing effect of disconnector parallel resistance on VFTO amplitude, frequencyand rise time, and discussed in detail the fast and slow GIS disconnector parallelresistance heat capacity, pointe out that disconnector is installed resistance also needs toconsider the actual situation of the substation、switch operating speed and resistance heatcapacity; Research the effect of disconnector operating speed on the residual charge andrekindle number, also pointe out that the disconnector operating speed has impact onthe arc pre-breakdown and arcing time characteristics.In computational process of VFTO,it is the critical factor that accurate description toarc produced in the process of disconnector operation,which has a great deal of effect onthe calculaton precision of VFTO. Dynamic arcing model was presented based onsegmental arcing model. In the pre-breakdown stage, hyperbolic resistance was used in themodel to consider the impact of breakdown delay time on VFTO waveform; in the extinction phase, complete Mayr model was established to describe the dynamic physicalprocesses of arc. Taking1100kV station as an example, paper calculated the amplitude,frequency and gradient of VFTO on the condition of two arcing models, and discussed theinfluence of breakdown delay time to VFTO waveform. It is found that VFTO has highermagnitude, higher frequency and higher gradient under dynamic arcing model; breakdowndelay time affects the initial rise time and amplitude of VFTO. By comparing simulationresults with the measured data, it is found that dynamic arcing model is the furtherimprovement of segmental arcing model and has great significance for improving theaccuracy of VFTO simulation.On the basis of dynamic arc model, paper discuss from thegap breakdown, high-frequency arc extinction criterion,building GIS disconnect switchingarc model to reflect repeatedly renewed, and simulate to VFTO based on this model.Due to high frequency effect, The MOA transient process is very complex,so it isnecessary to conduct in-depth research. The accuracy of MOA model is particularlyimportant, Currently,MOA electrical model under VFTO has not yet reached aconsensus. Based on analysising commonly MOA model, full consideration of thedynamic characteristics of the MOA in the high-frequency steep wave, this paperestablish the MOA dynamic transient model under VFTO. Taking UHV GIS substationas example, paper study the efftec of the MOA polarization model and the dynamictransient model to VFTO。The results show that, on condition of MOA dynamic transientmodel, VFTO has lower peak and increased high-frequency component and the shortestduration, and it is more suitable for VFTO simulation modeling.On the basis of theory of the multi-conductor transmission lines,GIS externaltransient model is modeled, combining with internal GIS model and The transient groundnetwork considered the mutual inductance role,this paper establish GIS overallsimulation model, On the one hand, the maximum values and spectral characteristics ofVFTO and TEV are analyzed in details. By comparison with the measured waveform,show that the simulation results on condition of GIS overall model are closer to the actualresults. Detailed analysis of the main TEV factors,put forward corresponding suppressionmeasures,it play a guiding role in the design and installation of GIS substation.更多还原