小波变换在输电线路行波故障测距中的应用

发布时间：2018-09-01 07:44

【摘要】：随着电网的发展,输电线路电压等级和输电容量逐步提高,输电线路故障对社会经济生活造成的影响越来越大。输电线路发生故障后,输电线路故障定位装置可为巡线人员提供准确、可靠的故障点位置信息,缩短故障查找时间,减轻线路巡视人员巡线负担,使输电线路能够很快恢复供电,还可以提前发现输电线路中的薄弱环节,有效地减少由于故障停电带来的经济损失。因此,输电线路故障测距是从技术上保证电网安全、稳定和经济运行的重要举措之一。本文首先介绍了小波变换的基本概念,分别从连续小波变换、离散小波变换以及二进小波变换三种小波变换情况,阐述讨论了小波变换的基本特点和基本性质。重点介绍了本文研究工作中所采用的基数B样条导数型小波基的定义、快速分解算法、小波生成和小波分解尺度如何选择。其次,分析输电线路故障后,暂态电压、电流行波的波过程,母线分支线路数量、短路过渡电阻等因素对行波测距的影响以及在测距计算中需要采用的解决方法。再次,介绍了单端行波测距算法及其实施步骤,通过EMTDC仿真对算法进行了验证。针对单端行波测距算法具有较高测距精度,但反射波识成功率较低的特点,提出了结合线路长度的反射波识别方法,通过仿真数据验证表明：相对于现有反射波识别法,识别成功率有所提高,改进了单端行波测距算法的测距可靠性。最后,介绍了双端行波测距算法及其实施步骤,通过EMTDC仿真对算法进行了验证。针对影响双端行波测距精度的过渡电阻、波速、线路参数等问题,本文研究中提出了基于多尺度分析的故障测距算法以及线路自修正的测距方法,并通过仿真数据进行了验证。
[Abstract]:With the development of power grid, the voltage level and capacity of transmission lines are gradually increasing, and the impact of transmission line failures on social and economic life is becoming more and more serious. After the fault of transmission line occurs, the fault location device of transmission line can provide accurate and reliable fault location information for line patrol personnel, shorten the time of fault finding, and lighten the line inspection burden of line patrol personnel. The power supply can be restored quickly and the weak links in the transmission line can be detected in advance, which can effectively reduce the economic loss caused by the failure of power supply. Therefore, transmission line fault location is one of the important measures to ensure the safety, stability and economic operation of power grid. In this paper, the basic concept of wavelet transform is introduced. The basic characteristics and properties of wavelet transform are discussed from three kinds of wavelet transform: continuous wavelet transform, discrete wavelet transform and dyadic wavelet transform. The definition of cardinality B-spline derivative wavelet basis, the fast decomposition algorithm, the wavelet generation and the selection of wavelet decomposition scale are mainly introduced in this paper. Secondly, the influence of transient voltage and current traveling wave process, the number of bus branch lines and short-circuit transition resistance on the traveling wave location and the solutions to the fault location are analyzed. Thirdly, the single-ended traveling wave ranging algorithm and its implementation steps are introduced, and the algorithm is verified by EMTDC simulation. In view of the high accuracy of single terminal traveling wave ranging algorithm, but the low success rate of reflection wave recognition, a reflection wave recognition method combined with line length is proposed. The simulation results show that the method is better than the existing method. The success rate of recognition is improved, and the reliability of single terminal traveling wave ranging algorithm is improved. Finally, the two-terminal traveling wave ranging algorithm and its implementation steps are introduced, and the algorithm is verified by EMTDC simulation. In this paper, a fault location algorithm based on multi-scale analysis and a self-correcting fault location method are proposed to solve the problems such as transition resistance, wave velocity and line parameters that affect the accuracy of two-terminal traveling wave ranging, and are verified by simulation data.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM75

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