基于超高频的局部放电在线监测系统的研究与开发

发布时间：2018-01-13 05:07

本文关键词：基于超高频的局部放电在线监测系统的研究与开发　出处：《兰州理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：随着国家电网的发展,封闭式气体绝缘组合电器(Gas Isolated Switcher GIS)被大量用在高压输配电系统中,它具有受外界影响小,运行稳定,检修周期长等诸多优点。对GIS的运行故障长期调查显示：绝缘损坏是造成GIS故障的主要原因。局部放电既是绝缘劣化征兆,又是加速绝缘劣化的主要原因,可以通过对局部放电的分析有效的了解GIS的绝缘状态。IEEE推荐在线局部放电检测是唯一有效绝缘实验,因此对GIS开展局部放电在线监测具有重要意义。对局部放电检测常见方法进行对比,确定本文采用超高频检测方法。超高频检测方法具有测量频率高,抗干扰性强,检测灵敏度高等特点在GIS局部放电监测中处于重要位置。从机理上进行分析研究局部放电产生的原因,列举造成这种现象的主要外在因素。分析电磁波在GIS内传播路径和基于最小光程差的局部放电定位原理,介绍局部放电表征参数。在研究集中式监测系统不足的基础上,致力于研发一套采用分布式结构的局部放电检测系统。数据的采集与处理在就地处理单元完成,在上位监测中心实现故障类型的判断,放电位置的定位。各个就地处理单元功能独立,个别单元的损坏和退出不会影响到上位机的正常工作,提高了系统运行的稳定和检测的灵活性。由于不同故障放电产生的信号其包络曲线不同,数据就地处理单元利用包络检波方式对超高频信号进行降频处理,解决超高频信号和采集系统之间的矛盾。以高速DSP为核心通过控制相关电路完成信号放大、滤波、采集,存储,并把经算法处理的数据上传到上位监测诊断中心。设计4种GIS常见放电现象的故障模型进行试验,采集放电信号的包络波形,以包络信号的特征为基础展开局部放电的模式识别和故障诊断。以小波包分解,核主元分析的方法提出包络曲线的特征信息,然后用BP神经网络对特征信息进行分类以验证该方法的有效性。系统软件开发分上位和下位两个模块,下位DSP系统的信号处理算法、控制程序的开发在CCS集成开发环境下以C语言完成,上位诊断分析软件的开发以面向对象的可视化开发工具VC++完成。
[Abstract]:With the development of State Grid, Gas Isolated Switcher GIS is widely used in high voltage transmission and distribution system. It has little external influence and stable operation. The long-term investigation of GIS operation fault shows that insulation damage is the main cause of GIS fault and partial discharge is the sign of insulation deterioration. It is also the main reason to accelerate insulation deterioration. It is the only effective insulation experiment to understand the insulation state of GIS effectively by analyzing partial discharge. IEEErecommended on-line partial discharge detection is the only effective insulation experiment. Therefore, it is of great significance for GIS to monitor PD on line. By comparing the common methods of partial discharge detection, it is determined that this paper adopts the ultra-high frequency detection method, which has high measuring frequency and strong anti-interference. The characteristics of high detection sensitivity are very important in GIS partial discharge monitoring. The mechanism of partial discharge is analyzed to study the cause of partial discharge. The main external factors causing this phenomenon are listed, the propagation path of electromagnetic wave in GIS and the principle of partial discharge location based on minimum optical path difference are analyzed, and the characterization parameters of partial discharge are introduced. Based on the lack of centralized monitoring system, a partial discharge detection system with distributed structure is developed. The data acquisition and processing is completed in the local processing unit. The function of each local processing unit is independent, and the damage and exit of individual unit will not affect the normal operation of the host computer. The stability of the system and the flexibility of detection are improved. Because the envelope curves of the signals produced by different fault discharge are different, the data processing unit uses envelope detection to reduce the frequency of UHF signals. To solve the contradiction between the UHF signal and the acquisition system. Using the high-speed DSP as the core, the signal amplification, filtering, acquisition and storage are completed by controlling the related circuit. The data processed by the algorithm is uploaded to the upper monitoring and diagnosis center. Four fault models of common discharge phenomena in GIS are designed and tested to collect the envelope waveform of discharge signals. Based on the characteristics of envelope signal, the pattern recognition and fault diagnosis of partial discharge are carried out, and the characteristic information of envelope curve is presented by wavelet packet decomposition and kernel principal component analysis. Then BP neural network is used to classify the feature information to verify the effectiveness of the method. The system software development is divided into two modules: upper and lower, and the signal processing algorithm of the lower DSP system. The development of the control program is completed in C language under the CCS integrated development environment, and the development of the upper diagnosis and analysis software is accomplished by the object-oriented visual development tool VC.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM855;TM595

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