基于非周期分量的变压器差动保护研究

发布时间：2018-04-28 00:27

本文选题：变压器差动保护 + 非周期分量　；参考：《西南交通大学》2015年硕士论文

【摘要】：变压器是电力系统中最常用和最基本的元件之一,其作用是在输电线路中提高电压等级,在配电线路中降低电压等级,其对整个电力系统运行具有重要意义。此外,由于大容量电力变压器自身的成本高,其损坏时造成的经济损失非常巨大。传统的工频纵联差动保护因其灵敏度高和实现简单等优点而被广泛的应用于电气设备中,但是,其在变压器的应用中仍存在一些问题,如需要躲避不平衡电流、无法判别微小匝间短路和存在励磁涌流识别等问题。因此,本文将一种基于非周期分量的差动保护应用到变压器保护中,来提高保护动作性能,同时,验证该保护识别微小匝间短路故障和励磁涌流的有效性。首先,本文简要分析了电磁式电流互感器的工作过程,存在的问题和解决方法。对比分析得出光学电流互感器具有无磁饱特性和能够准确提取故障非周期分量电流的特点。在此基础上,分析基于非周期分量电流的纵联差动保护,并采用一个全波内积分的方法实现非周期分量的提取。然后,本文分析了变压器现有的纵联差动保护原理及其判据,分析不平衡电流和励磁涌流产生的原因及其对变压器纵联差动保护的影响,重点对比分析了常用的励磁涌流鉴别方法及其各自特点。最后,本文将基于非周期分量的线路差动保护应用到变压器保护中,分析得到该保护比率差动和方向差动的判据。通过MATLAB/Simulink软件构建变压器双端电源、单端电源和匝间短路故障的仿真模型,仿真验证了该保护动作的正确性及其识别微小匝间短路故障和励磁涌流的能力。同时,仿真分析了不同时刻、过渡电阻和故障类型对该保护特性的影响。本文理论分析和仿真验证表明：基于非周期分量的纵联差动保护在变压器保证中灵敏性要优于传统保护；该保护不用借助其它的方法即可识别励磁涌流,其亦可用于保护匝数大于3.6%的匝间短路故障。本文的研究成果对于非周期分量在变压器差动保护中的应用、判定微小匝间短路故障和识别励磁涌流具有参考价值。
[Abstract]:Transformer is one of the most common and basic components in power system. Its function is to improve the voltage level in transmission lines and to reduce the voltage grade in distribution lines, which is of great significance to the operation of the whole power system. In addition, because of the high cost of large capacity power transformer itself, the economic loss caused by its damage is very huge. Traditional power frequency longitudinal differential protection is widely used in electrical equipment because of its high sensitivity and simple realization. However, there are still some problems in transformer application, such as the need to avoid unbalanced current. It is impossible to distinguish the small inter-turn short circuit and the identification of inrush current. Therefore, a kind of differential protection based on aperiodic component is applied to transformer protection to improve the performance of the protection. At the same time, the effectiveness of the protection in identifying micro-inter-turn short-circuit faults and excitation inrush current is verified. Firstly, this paper briefly analyzes the working process, existing problems and solutions of electromagnetic current transformers. The comparison and analysis show that the optical current transformer has the characteristics of non-magnetic saturation and can accurately extract the fault aperiodic component current. On the basis of this, the longitudinal differential protection based on aperiodic component current is analyzed, and a full wave integral method is used to extract the aperiodic component. Then, this paper analyzes the principle and criterion of transformer longitudinal differential protection, analyzes the causes of unbalanced current and excitation inrush current and its influence on transformer longitudinal differential protection. The common identification methods of inrush current and their respective characteristics are compared and analyzed. Finally, the line differential protection based on aperiodic component is applied to transformer protection, and the criterion of ratio differential and directional differential protection is obtained. The simulation model of transformer double end power supply, single end power supply and inter-turn short circuit fault is constructed by MATLAB/Simulink software. The simulation results show that the protection action is correct and the ability to identify micro inter-turn short circuit fault and excitation inrush current is verified. At the same time, the effects of transition resistance and fault type on the protection characteristics are analyzed. The theoretical analysis and simulation results show that the sensitivity of the differential protection based on aperiodic component is superior to that of the traditional protection, and the inrush current can be identified by other methods. It can also be used to protect short circuit faults with turn number greater than 3.6%. The research results in this paper have a reference value for the application of aperiodic component in transformer differential protection, the determination of micro-turn short circuit fault and the identification of inrush current.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM774

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