论文总字数：25818字

摘 要

学号：16012325 姓名：李科旭

指导教师：林鹤云教授

真空断路器作为电力系统中的一类开关设备，在电网的安全运行中发挥着重要作用，它可以实现智能化操作，从而迅速、准确判断电路情况，对短路故障进行切除，有效地减少短路故障对电力系统的危害，保障电网稳定可靠运行。

随着相控开断技术地发展，目前的一个重点研究方向是将真空断路器与相控开断技术相结合，实现了真空断路器的智能化操作。然而，当今故障电流相控开断技术并不完善，仍存在许多需要解决的问题。本文着重研究单相短路情况下，真空断路器在故障后的选相，初始时刻判定以及智能开断短路故障的方案，为短路电流的相控开断奠定理论基础。

首先进行短路故障选相和故障时刻判定，利用相电流差突变的方法进行故障相判定，对于故障时刻的获取则利用小波分析的方法。其次，对故障电流模型进行深入地研究，推导出故障电流数学表达式，在仿真软件中搭建单相短路故障电流模型，通过仿真研究相关参数对电流零点产生的影响。最后依据算法的原理和流程，编写相应的算法并对安全点算法、自适应算法、半波傅氏算法进行仿真分析，验证算法的可行性。

仿真结果表明，这三种算法都可以实现零点的预测，并且算法的精度在允许范围内。通过对算法的仿真验证，分析得出了不同算法的特征及其适应性，为实际运用中算法的选择提供了依据。

关键词：真空断路器；故障电流；相控开断；零点预测算法

ABSTRACT

As a class of switching equipment, vacuum circuit breaker plays an important role in the safe operation of the power grid. By realizing intelligent operation, vacuum circuit can make a judgment of the operating status of power system quickly and accurately, and then remove the short circuit fault to reduce its harm to power system, through which to guarantee power grid’s safe and reliable operation.

With the development of phase-controlled interruption, one of the key researches is the combination of this technology with vacuum circuit breaker, which can realize the intelligent operation of vacuum circuit breaker.Nowadays, however, the phase-controlled interruption technology is not perfect and there are still many problems which need to be solved. This thesis focuses on the location of fault phase, the judgment of fault’s initial time and the method to intelligently interrupt short-circuit fault from the perspective of single phase short circuit fault in power system, through which to lay a theoretical foundation for the phase-controlled interruption of short-circuit fault.

First of all, the fault phase and short circuit fault time have to be determined. According to the difference between the values of electric current, the fault phase can be identified. The moment of short circuit occurred can be determined according to the result of wavelet analysis. Secondly, this thesis makes a deep research on the model of failure current and the derivation of its mathematical expressions. Then, a one-phase short-circuit fault model was built up in simulation software. Through the analysis of simulation results, the impacts of related parameters on the current zero point can be obtained. Finally, programs related to the proposed algorithms have been written according to the principle and process of algorithms. Simulations about safe-points algorithm, adaptive algorithm and half-wave Fourier algorithm have been implemented to verify the feasibility of algorithms.

The simulation results show that these three algorithms can predict the current zero-cross point and the accuracy of the algorithm is in the allowable range. Through the simulation, the characteristics and suitability of different algorithms have been obtained, which provides guidance for the choice of the algorithm. In the end, a conclusion of this thesis and the prospect of the future work are drawn.

KEY WORDS: Vacuum circuit breaker；Fault current；Controlled interruption；Algorithm of zero-cross point foreeas

目 录

摘 要 I

ABSTRACT II

第一章 绪 论 1

1.1电力系统短路故障概述及其影响 1

1.1.1短路故障概述及其原因 1

1.1.2 短路的现象及其危害 1

1.2 真空断路器相控开断技术 2

1.2.1相控开断技术原理 2

1.2.2相控开断技术的国内外研究现状 5

1.2.3短路故障相控开断的优势和难点 6

1.3本文的主要内容 7

1.3.1本文的主要工作 7

1.3.2本文的章节安排 8

第二章 单相短路故障选相及初始时刻判断 9

2.1 电力系统短路故障相的判别 9

2.1.1 短路故障模型及其特点 9

2.1.2 故障相判别方法 9

2.1.3判别方法仿真验证 10

2.2短路故障初始时刻判断 11

2.2.1小波分析法原理 11

2.2.2基于小波分析的故障初始时刻判定 11

2.3本章小结 13

第三章 短路故障电流模型的推导及参数分析 14

3.1故障电流模型的推导 14

3.2相关参数对电流零点的影响 15

3.2.1电压初相角的影响 16

3.2.2时间常数的影响 19

3.3本章小结 20

第四章 电流零点预测算法的研究与仿真验证 21

4.1 安全点算法 21

4.1.1安全点算法的概述 21

4.1.2 安全点的概念 21

4.1.3 安全点的计算方法 22

4.1.4 安全点算法的仿真验证 23

4.2自适应算法 26

4.2.1自适应算法概述 26

4.2.2自适应算法原理 26

4.2.3自适应算法的仿真验证 28

4.3半波傅氏算法 32

4.3.1半波傅氏算法概述 32

4.3.2半波傅氏算法原理 32

4.3.3半波傅氏算法的仿真验证 33

4.4零点求取方法 34

4.5 三种零点预测算法的对比 34

4.6基于C 语言的算法实现 34

4.7本章小结 36

第五章 总结与展望 37

参考文献 38

致谢 41

第一章 绪 论

1.1电力系统短路故障概述及其影响

在当今这个工业技术与电力系统飞速发展的时代，电力系统的负荷密度也有日益增加的趋势。当短路故障发生时，回路中的电流会迅速上升，短路电流值甚至为该回路额定电流的数倍。短路电流对电气设备运行的安全与稳定造成了严重的危害。

1.1.1短路故障概述及其原因

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