【作者】 龙锋；

【导师】 王富荣；

【作者基本信息】 西南交通大学 ， 电力系统及其自动化， 2004， 硕士

【摘要】 高压电气设备绝缘的劣化、失效是一个缓慢的过程，变电站内电容型设备数量很多，一旦发生失效，造成的损失或影响很大。因此，电力部门制订了定期预防性维修制度，但是定期预防性试验存在一些缺陷，有时候不能真实地反映设备的绝缘状况，还会造成大量的人力物力的耗费。因此，把在线监测技术引入到绝缘在线监测中来，对电容型设备的运行状态进行实时监测，及早地发现设备的绝缘故障，使电容型设备从定期维修转变为状态检修，成为电力部门需要迫切解决的问题。 本文在阐述介质损耗因数物理概念的基础上，以电容型设备介质损耗因数和电容量作为反映绝缘状况的特征量，采用基于傅立叶变换的谐波分析法，通过快速傅立叶变换计算出由传感器获得的被测设备运行电压信号和泄漏电流信号基波傅立叶系数，进一步求出二者的相位差，计算出介质损耗因数。 其次，本文采用分层分布式结构作为介质损耗因数在线监测系统的结构形式，设计了在线监测系统的前端数据采集装置，主要负责数据的采集、处理以及和上位PC机的数据通信。为减少快速傅立叶变换泄漏效应和栅栏效应的影响，提高快速傅立叶变换的精度，软件上采用对采样序列进行加窗处理的方法，硬件上采用锁相倍频电路配合A／DC完成对两路信号的同步整周期采样。前端数据采集装置和后台上位机之间数据通信采用RS485总线，设计了RS485通信接口电路和通信协议。完成了在系统的软件设计，主要包括系统主控程序、A／D采样子程序、数据通信程序以及FFT计算子程序。 最后，对在线监测系统的抗干扰问题作了论述，提出了一些抗干扰措施。更多还原

【Abstract】 The aging and invalidation of high voltage electric power equipments insulation is a slow process. There are many capacitive equipment in the transformer substation. Using the dielectric dissipation factor and capacity as the characteristic parameter to reflect the insulation status and by analyzing the measures, we can make an impersonal evaluation to the equipments’ insulation performance. So it can enhance the stability and reliability of insulation system.Firstly in this paper, the important significance of developing the on-line monitoring about the insulation, the technique status actualities and the development trend of this project in the world is narrated. In succession it expounds the physics concept of dielectric dissipation factor and introduces the digital wave analytical method based on the Fourier Transform. By the Fast Fourier Transform the fourier coefficients of the base wave both normative voltage signal and leakage current can be calculated. Then through working out the phase angle difference between them, it is easy to figure out the dielectric dissipation factor. In order to reduce the influence of the leakage effect and the barrier effect and advance the precision of the Fast Fourier Transform, the Windows function is adopted to the sampling serials.Secondly, selecting the distributing system as the structure of the on-line monitoring system, giving the circuit of data acquisition device. It takes charge of sampling data, disposing data and communicating with the topper computer. The DSP CMOS chip TMS320F206 is selected as the CPU. Cooperating with the magnifying circuit, filter circuit and PLL circuit, it is easy to realize the synchronizing and whole periodic sampling. The data communicating between the data sampling unit and the computer adopts RS485 fieldbus. At the same time, the communication protocols and RS485 communication interface are designed. Subsequently, the software for the data-acquisition unit is designed. The software is made up of the main program, A/D sampling data sub-program and the communication sub-program.At last, the paper discusses the anti-jamming problem of the on-line monitoring system and puts forward some anti-jamming measure.更多还原