【作者】 陈丽；

【导师】 蒋文科；

【作者基本信息】 河北农业大学 ， 农业机械化工程， 2004， 硕士

【摘要】 电力设备绝缘检测是保证安全发、配电，及时发现事故隐患、提高供电可靠性的重要技术手段。随着电力事业的迅速发展以及对电力系统运行可靠性要求的进一步提高，电气设备在线检测技术的发展日益得到重视。高压电容型设备在变电站中占有相当大的比例，而介质损耗因数(tan δ)是反映其绝缘状况的重要参数。因此，研究电容型设备的tan δ在线检测技术具有十分重要的意义。 采样系统的性能对数字化介质损耗测量的精度有非常重要的影响，文中结合谐波分析法介质损耗在线检测的特点和要求，对影响采样系统性能的主要参数——采样位数和采样频率进行了详细的分析，得出了它们对测量误差的影响规律，并在此基础上给出了确定最佳采样频率和采样位数的原则和方法。 为了更好地保证tan δ在线检测的准确性，文中把数字滤波技术应用于tan δ在线检测，利用布莱克曼窗函数的设计方法设计了有限长冲激响应的数字滤波器，仿真表明该滤波器具有良好的滤波效果。 文中针对国内外在进行电容型设备介质损耗因数在线检测研究中存在的技术难点，如电网基波频率不稳、高次谐波干扰、现场电磁干扰等问题，提出了将加窗插值的快速傅立叶变换算法应用于tan δ测量。这种方法与传统的快速傅立叶变换算法相比，避免了由于基波频率提取不准而造成的频谱泄漏，在一定的基波频率变化范围内具有较高的精度。 本文在研究以上理论问题的基础上，本着准确度高、实用性强、成本低、可靠性好的原则，研制了一种电容型设备tan δ在线检测装置。在对装置进行设计的过程中，通过对各个环节进行理论分析和对部分环节进行仿真计算，使装置的设计结果达到了预期的设计目标。更多还原

【Abstract】 The on-line insulation monitoring of power apparatus is very important to guarantee the safety of power delivery, find insulation faults in time and increase the reliability of power supply. With the development of electrical engineering and the further demand on the service reliability of power systems, the on-line insulation monitoring has been put more value on. high voltage capacitive-type equipment plays a very important role in power systems, and dielectric loss tangent (tan5) is an important parameter to reflect its insulation condition. Therefore, the study on the on-line tan5 monitoring of high voltage capacitive-type equipment has practical values.The measured results are greatly influenced by the property of the wave sampling system. Two parameters: sampling accuracy and sampling frequency, which are the most important ones for sampling system, are discussed deeply. The way how these two parameters affect the performance of sampling system is concluded. On the basis of these, the principle and the method of determining the optimal sampling parameters are presented.For the sake of assuring the accuracy of the measured results of tan8 better, digital filtering algorithm is introduced to the measurement of tan8. A kind of FIR digital filter is designed, simulation indicates that the designed filer has satisfying effect.Considering the difficulties of on-line monitoring research of the high voltage capacitive-type equipment local and overseas, such as the excursion of the fundamental wave of power system, the existence of the harmonics and the electromagnetic interference, Windows and Interpolation Fast Fourier Transform algorithm is applied to the measurement of tan. With this method, the spectrum leakage can be avoided more effectively than Fast Fourier Transform algorithm and better accuracy can be assured in certain frequency range.On the basis of the study of the theories above, a kind of on-line tan 5 monitoring system of high voltage capacitive-type equipment is developed which follows the principles of high accuracy, strong utility, low cost and high reliability. During the designing, every step is analyzed theoretically and parts of steps are simulated, the design of the monitoring system obtains anticipated purpose.更多还原