【作者】 王颖；

【导师】 杜伯学； 李玉林；

【作者基本信息】 天津大学 ， 电气工程， 2010， 硕士

【摘要】 电力行业作为我国国民经济发展的重要支柱性产业,对我国经济的快速发展具有非常重要的意义。其中高压直流输电因为具有距离长、容量大、控制灵活等优点,近年来,直流输电方式及相应的直流输电设备在国内外的电力行业中都有较快的发展。随着电网规模的不断扩大,电压等级的逐步提高,对系统的可靠性、稳定性等方面提出了更高的要求。同时,对直流电气设备运行状态的安全性也提出了进一步的要求。在电力系统中,使电气设备产生故障的原因有很多,这其中由绝缘损坏引起的故障所占的比重最大。导致绝缘损坏的原因很多,而由局部放电导致的电气设备绝缘劣化是重要原因。所以在绝缘状态检测中局部放电检测占有非常重要的地位。本文首先从局部放电的理论入手,通过局部放电的概念、种类、原理、特点及直流局部放电机理等局部放电的理论,全面的介绍了局部放电的含义。然后在交流局部放电检测系统的基础上,搭建起了直流局部放电检测系统,用高频CT法对直流局部放电的信号进行检测,选取了典型的局部放电模型：电晕放电、内部放电、悬浮电位放电,在不同外加直流电压作用下,进行了直流局部放电的实验。通过分析,提出了放电幅值与放电次数之间的关系以及放电时间间隔与放电次数之间的关系可作为直流局部放电模式识别的图谱。最后,在直流局部放电实验的基础上,将不同类型的直流局部放电特征量进行了分析比较,提取了局部放电图谱的偏斜度和陡峭度作为直流局部放电类型识别的特征量；证明它们可以有效地识别直流局部放电的类型。更多还原

【Abstract】 As a major pillar industry of gross domestic economic development of China, power industry plays an extremely important role. High Voltage Direct Current Transmission can transfer heavy capacity to far distance, and it can be controlled flexibly. In recent years, the HVDC have developed rapidly in the power industry all over the world, and as well as the DC voltage electrical equipment. Along with the enlarging of the power network and the increasing of the voltage level, the security and stability of the power system would be higher. At the same time, the security on the running state of DC electrical equipment would be advanced, too.Many reasons can lead to the insulation failure of electrical equipment. The partial discharge is an important reason for leading to the insulation deterioration of electrical equipment. So the partial discharge occupies a very important position in insulation test.First of all, this paper begins with the partial discharge theory, such as the definition, the categories, the elements, the characteristic of the partial discharge. And then introduces the mechanism of the partial discharge at DC voltage, in order to give a comprehensive summary of it. Based on the AC partial discharge testing system, we seted up the testing system of partial discharge at DC voltage. We test the signal of the DC partial discharge by the way of HFCT. And three typical discharges models are choosed. They are corona discharge, internal discharge and suspending discharge. The tests are done at different DC voltage. Based on the analysis, the relationship between the partial discharge amplitude and its number and the relationship between the time interval of discharge and its number are selected as PD pattern to identify its type. Finally, based on partial discharge tests at DC voltage, the article analyses and compares the characteristic parameters of the different type of the DC voltage partial discharge. The statistical characteristic parameters, including skewness and kurtosis, are selected as the partial discharge characteristic parameters at DC voltage; they can be used to effectively identify the types of partial discharge at DC voltage.更多还原