毕业论文《电网谐波的危害及抑制技术》.doc

摘要 随着电力系统的发展以及电力市场的开放，电能质量问题越来越引起广泛关注。由于各种非线性负载(谐波源)应用普及，产生的谐波对电网的污染日益严重。因此，谐波及其抑制技术己成为国内外广泛关注的课题。 在电力电网中，存在大量非线性负载,引起电网电流波形不再是正弦波。这一非正弦波可用傅里叶级数分解成为一个直流量，基波正弦量和一系列频率为基波频率整数倍的高次谐波正弦分量之和。各国对电力电网电压正弦波形畸变的极限值都有明确的规定，要求用户对接入电网的设备产生的谐波应采取一定措施，进行抑制。 现代电力系统集发电、变电、输电、配电和用电于一体，涉及范围广，且元件繁多，结构复杂。为了确保电力系统的安全、可靠、经济运行，以及一旦发生故障后，能快速地消除或隔离故障，尽快恢复正常运行，在电力系统中需要大量的高新技术。本文从谐波的产生、谐波抑制技术、电力滤波器原理及应用、基于小波的电力系统谐波分析四个方面来研究电网谐波，并通过对算法仿真要用到的谐波信号进行了建模，这些信号模型都是根据实际电网信号进行分类建模得来的，虽然具有理想化的特点，但是并不影响对算法本身优劣性能的影响。总之谐波抑制的目的在于能够更好的在工农业生产中减少电力谐波所带来的危害，创造更优质的电能来为人类的生产生活提供保障。 关键词：电网 谐波危害 非线性负载 抑制技术 Abstract With the development of the power system and opening-up of electricity market, power quality is arousing increasingly attention widely. As the universal application of non-linear loads (harmonic sources), the pollution on power caused by the harmonic is becoming increasingly serious. Therefore, harmonic and its suppression technologies has become the subject of domestic and international scientists. There are a large number of nonlinear loads in the electricity grid, while what caused grid current waveform is no longer a sine wave, and this non-sinusoidal wave can be broken down into, according to the Fourier series, a direct flow, the fundamental sinusoid and a range of high-order harmonic sinusoidal component whose frequency is an integer multiple of the fundamental one. Each country has a clear provision about the limits on the power grid voltage sine wave distortion, which also requires the users take certain measures to suppress the harmonics generated by the equipment connected to the grid. Modern power system sets power generation, substation, transmission, distribution and electricity as one, involving a wide range of components and complex structure. In order to ensure the safety, reliability of the power system’s operation, and quickly eliminate the problem and resume to normal operation as soon as possible in the event of failure, a lot of high-techs are needed in the power system. This pa