输电线路微风振动在线监测的研究与设计

发布时间：2018-08-22 17:59

【摘要】：输电线路微风振动的发生会造成输电线和电力金具的损坏,对电网稳定和可靠运行造成严重影响。近年来随着人们用电需求量的增大,输电线的输送容量和输送距离都有所增加,再加上悬挂点高度的增加,使微风振动发生的概率大大增加。输电线路微风振动的隐蔽性很强,而且微风振动对架空线的破坏是一个长期积累的过程,不可能通过直接观察的方式来衡量其破坏程度。如何准确实时地监测架空输电线路的运动状态至关重要,目前国内通用的方法一般是采取位移传感器来监测微风振动,但存在抗电磁干扰能力弱及不易测量到小幅振动的问题。电力部门迫切需要一种能够有效避免电磁干扰、安装简易、测量精度高的微风振动监测设备。本文基于对微风振动在线监测国内外现状的了解,研究了微风振动的形成原因、主要影响因素及其测量原理和方法,着重介绍了导线振动的动弯应变计算。同时对微风振动监测数据处理方法进行了研究,介绍了最小二乘法、快速傅里叶变换法和基于小波降噪的FFT三种处理方法并进行对比分析,为测量精度的提高做好理论准备。文中简要描述了微风振动在线监测系统的整体架构,并设计了一套振动监测单元,其通过加速度传感器采集振动加速度信息,并通过2.4G无线通信模块与监测子站通信,保证了信息传输的稳定性。另外为了使振动监测单元能在恶劣的环境下不断电工作,本设计增加了电源保护电路。结构上采用全封闭铝制外壳实现等电位工作,避免了传感器与导线直接接触,可避免线上高电压进入到线路板。在软件设计方面,为提高其信息处理准确度,采用小波变换法对振动信号去噪,再通过快速傅里叶变换进行频谱分析,进而计算出导线的动弯应变。无线通信模块的软件设计保证振动监测单元能够和监测子站实时、准确通信。本文利用振动台对所设计的振动监测单元进行了实验,测试所设计装置的精确度以及稳定性。实验结果表明,实测数据可靠,其中时域幅值和频率误差均小于3%。
[Abstract]:The wind vibration of transmission lines will cause damage to transmission lines and power fittings, which will seriously affect the stable and reliable operation of the power grid. In recent years, with the increasing demand for electricity, the transmission capacity and distance of transmission lines have been increased, and the height of suspension points has increased, which greatly increases the probability of wind vibration. The transmission line has strong concealment of the breeze vibration, and the destruction of the overhead line caused by the breeze vibration is a long-term accumulation process. It is impossible to measure the damage degree by the way of direct observation. How to accurately and real-time monitor the moving state of overhead transmission lines is very important. At present, the common method in China is to use displacement sensors to monitor the vibration of the breeze, but there are some problems such as weak ability of resisting electromagnetic interference and difficulty in measuring small vibration. The electric power department urgently needs a kind of wind vibration monitoring equipment which can effectively avoid electromagnetic interference, install easily and measure accurately. Based on the current situation of on-line monitoring of wind vibration at home and abroad, this paper studies the causes of wind vibration, the main influencing factors and its measuring principle and method, and emphatically introduces the calculation of dynamic bending strain of conductor vibration. At the same time, the data processing method of wind vibration monitoring is studied, and three processing methods, least square method, fast Fourier transform method and FFT method based on wavelet noise reduction, are introduced and compared and analyzed, so as to prepare the theory for the improvement of measurement accuracy. This paper briefly describes the whole structure of the on-line monitoring system of the breeze vibration, and designs a set of vibration monitoring unit, which collects the vibration acceleration information through the acceleration sensor and communicates with the monitoring sub-station through the 2.4G wireless communication module. The stability of information transmission is guaranteed. In addition, in order to make the vibration monitoring unit work without power off in the bad environment, the power supply protection circuit is added in this design. In the structure, the fully enclosed aluminum shell is used to realize the equipotential operation, which avoids the direct contact between the sensor and the wire, and prevents the high voltage on the line from entering the circuit board. In the aspect of software design, in order to improve the accuracy of information processing, the vibration signal is de-noised by wavelet transform, and the frequency spectrum is analyzed by fast Fourier transform, and the dynamic bending strain of conductor is calculated. The software design of the wireless communication module ensures that the vibration monitoring unit can communicate with the monitoring substation in real time and accurately. In this paper, the designed vibration monitoring unit is tested by using the vibration table, and the accuracy and stability of the designed unit are tested. The experimental results show that the measured data are reliable and the time-domain amplitude and frequency errors are less than 3.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM75;TP274

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