毕业论文--变压器局部放电的测量及影响因素的分析.doc

哈尔滨工业大学工学硕士学位论文 哈尔滨理工大学学士学位论文 - PAGE II - - PAGE II - 变压器局部放电的测量及影响因素的分析 摘要 大型变压器是电力系统中的关键设备之一。在大型变压器运行的过程中，严重的电、热和环境应力的联合作用将导致绝缘结构中的薄弱部位发生局部放电并不断发展，直至绝缘击穿。对变压器的局部放电检测在当今也变得愈发重要。了解影响变压器局部放电测量的因素对于生产实际有着十分重要的意义。 本文简单介绍了变压器局部放电的产生原因、表征参数和放电类型，并介绍变压器局部放电检测技术的现状，分析了脉冲电流法、超声检测法化学检测法等方法的基本原理。着重分析了局部放电信号在变压器绕组中的传播特性，得到放电脉冲在绕组中的衰减特性和单个变压器绕组的频率特性。分析了局部放电信号在变压器油纸绝缘的产生与传播，得到一些影响变压器局部放电测量的因素。另外对于常用的脉冲电流法进行了误差分析，并对新兴的超高频检测法的影响因素作了简单介绍。 关键词　变压器；局部放电测量；绕组特性；油纸绝缘 The analysis of partial discharge measurement and the affecting factors in transformer Abstract Large-scale transformer is one of the most important apparatus in power system. In the process of large-scale transformer operation, severe combined effects of electrical, thermal and environmental stress will lead to the weak parts in the insulation structure of partial discharge occurs and continuous development until the insulation breakdown. Transformer partial discharge detection has become increasingly important in nowadays. Factors that affect transformer partial discharge measurements for the actual production is of great significance. This paper briefly describes the causes of transformer partial discharge characterization parameters and discharge type, and describes the status of transformer partial discharge detection techniques, the basic principle of the pulse current method, ultrasonic testing method of chemical assay methods. The paper also analyzes the propagation characteristics of partial discharge signals in transformer windings, the frequency characteristics of the discharge pulse attenuation characteristics in the windings and a single transformer winding. It analyzes the generation and propagation of partial discharge signals in oil-paper insulation of transformer. We can get some of the impact of transformer partial discharge measurements on factors. In addition to error analysis of the commonly used pulse current method, and emerging UHF detection method of influencing factors is briefly introduced. Key