【作者】 何柏娜；

【导师】 林莘；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2011， 博士

【摘要】 特高压输电是当前我国电力系统领域研究的热点,在我国“西电东送,南北互供,全国联网”的电力发展战略中扮演重要的角色。电压等级的提高给特高压输电系统绝缘带来了严峻的挑战,限制特高压输电系统的过电压水平,合理选择绝缘水平是特高压输电工程建设的关键课题。因此研究特高压输电线路的过电压及自适应重合闸技术具有重要的现实意义。本文针对特高压输电线路发生单相接地故障后的暂态特性,将从瞬态恢复电压、线路感应电压、潜供电弧熄灭特性等几个方面对特高压电网的过电压进行深入、细致地研究。作了如下几方面的研究工作：根据特高压示范工程线路的实际结构及GIS (Gas Insulated Switch)内部结构建立仿真模型,对瞬态恢复电压进行研究。本文首次分析了线路间的静电感应和电磁感应现象对瞬态恢复电压的影响,并进行详细的理论推导；仿真分析不同故障类型及不同故障位置处的瞬态恢复电压,以及考虑感应电压影响前后瞬态恢复电压参数的变化情况。通过分析可知感应电压使瞬态恢复电压的峰值和上升率有所增加,这对断路器的绝缘水平提出更高的要求,对断路器结构设计具有一定的理论指导作用。采用频率相关参数模型对特高压输电线路上潜供电弧产生的物理过程进行详细的分析并对潜供电弧参数进行系统的理论推导,分析恢复电压和潜供电流的变化规律；分析单相瞬时性故障情况下的一次电弧和二次电弧的数学模型,建立电弧的仿真模型。利用已有的试验结果对本文的计算结果进行验证,验证结果表明本文建立的电弧模型以及线路模型的思想是可行的,得到的计算结果是合理的。利用已建立的电弧模型和线路模型搭建特高压示范线路系统模型,对实际输电线路进行相关的潜供电弧特性仿真研究。得到不同故障性质情况下的故障相端电压电流波形,利用傅里叶变换对其进行分析,重点对二次电弧阶段的变换结果进行了对比和分析,从而提取出能够区分故障性质的关键特征。最后通过大量的仿真得到训练样本和测试样本,最后利用模糊神经网络实现自适应单相重合闸。最终的仿真结果证明了本文提出的自适应单相自动重合闸方法的有效性和正确性。更多还原

【Abstract】 The ultra-high-voltage (UHV) transmission system takes an important part in China electrical power development. The issue of insulation becomes more and more outstanding with the increase voltage classification. The restriction of overvoltages and the proper selection of insulation coordinations are the key subject in UHV transmission engineering construction. Therefore the research on overvoltage and adaptive auto-reclosing technique for UHV transmission line is of great practical significance.The paper focuses on the transient characteristics of single-phase earth fault on UHV transmission line. Several aspects of overvoltage are studied in-depth on UHV power grid, including transient recovery voltage, line induced voltage, extinction characteristic of secondary arc. Several research aspects as the following:According to structural characteristics of the actual line and interal structure of GIS to set up the simulation model of the whole system. The paper first analyzes the effect electrostatic induction and electromagnetic induction on the transient recovery voltage, and conducts a detailed theoretical derivation. The paper simulates and analyzes transient recovery voltage under different fault types and different fault locations, and transient recovery voltage parameters changes after considering the effect of induced voltage. Analysis showed the induced voltage can increase the peak of transient recovery voltage, which bring forward higher requirements for the circuit breaker insulation level and provide theoretical basis for structural design of circuit breaker.The paper adopts frequency related parameter model on the transmission of UHV to analyze the physical process secondary arc and carry on the detailed theoretical derivation of the secondary arc parameters, and analyze the variation regularity of recovery voltage and secondary arc current, analyzes the mathematical models of the primary arc and the secondary arc under the temporary single-pole fault, and establishes the simulation models of arc. The computation results in this paper are testified by theformer test results and the maturity results. It is feasible that the idea based on establishing arc model and circuit model, and the calculation result is reasonable.The paper simulates and studies characteristic of secondary arc of the actual transmission line through establishing system model UHV demonstration project. The waveform of the voltage of faulty phase under the different type of fault is simulated by EMTP-ATP. Then, the voltage of faulty phase is transformed by the Fourier transform. In order to extract the key features which can be used to distinguish the type of fault, the transformation of the voltage of faulty phase in the period of secondary arc should be pay more attention to. Finally, training samples and the testing samples are obtained by lots of simulation, and single-pole adaptive reclosure based on transient component is realized by fuzzy neural network. The finally simulation results show that the method proposed in this paper of single-pole adaptive reclosure is correct and effective.更多还原