【作者】 禹水琴；

【导师】 史燕；

【作者基本信息】 西南交通大学 ， 计算机应用， 2006， 硕士

【摘要】 电力电缆故障是电力系统中的常见问题,电缆测距是排除电缆故障的前提条件,准确的电缆测距可以缩短发现故障点的时间,有利于快速排除故障,减小由电缆故障带来的损失。 本文深入研究了低压脉冲反射法的原理,深入理解该方法得到的入射波和反射波的基本规律和特点。运用小波变换的多分辨率和模极大值特性,提出了一种电缆故障点自动定位方法。运用MATLAB仿真,得到较好的效果。本文根据真实信号和噪声信号在小波分析各尺度上不同的传播规律,采用了改进的软阈值消噪法,有效地促进了信噪分离,提高了采集信号的信噪比。分析了行波法存在着无法解决的问题,结合故障点自动定位法和电流差测距法,采用一种可以解决行波法无法解决的问题,通过仿真得到了较好的结果。 对行波法测距法和电流差测距法的原理、优点、缺点进行了详细具体地比较。对本文提出的故障点定位法与记点数故障点定位法的原理、优点、缺点进行了详细具体地比较。更多还原

【Abstract】 Power cable fault occurs regularly in power system. Fault location is necessity to eliminate the fault. Accurate fault location can reduce the time to find out the fault point and the cost of power cable cut.The principle of the low voltage pulse method is deeply investigated .The necessity disciples and characteristic of the incidence wave and the reflect wave are also deeply investigated. Using multi-resolution and maximum value of the wavelet transform, a method of transmission line fault location is devised. Using MATLAB to simulation this method, we get a good result. The improved wavelet soft-threshold method is presented based on the different propagation property of real signals and white noises under the wavelet transform. It can accelerate the separation of the signal from the noise and get higher SNR for the reconstructed signal. Analyze the inextricable problem of the method based on traveling wave, we using the method based on the subtraction of two electrical currents to resolve the problems and this method obtains a good result through the simulation.The principle, excellence and disadvantage of the method based on traveling wave and the method based on the subtraction of two electrical currents are compared in details. The principle, excellence and disadvantage of the method of transmission line fault point location and another method of transmission line fault point location witch expound in this thesis are compared.更多还原