【作者】 阎冬；

【导师】 王葵；

【作者基本信息】 山东大学 ， 电力电子与电力传动， 2010， 硕士

【摘要】 随着电力电子技术的发展,基于各种电力电子装置的非线性设备得到了迅速的普及和发展,各行业使用的换流设备数量越来越多、容量越来越大,电弧炉和电气化铁路等产生的谐波电流注入电网,都造成了谐波成分的上升。谐波不仅使公用电网电压波形畸变现象愈加严重,电能质量严重下降。因此,把公用电网谐波量控制在适当的范围内,防止谐波造成的危害,从而保证电力系统安全经济运行,成了大家普遍关心的问题。电力系统是一个整体,其电能质量状况相互影响,对新入网的用户谐波情况进行评估预测并提出适当的治理方法,为新上非线性用户入网前的建设和规划提供参考是更经济可行的办法。本课题分析了我国关于电力系统谐波问题制定的相关标准,在此基础上针对电能质量谐波评估和治理的理论和方法进行研究。考察了目前对电能质量问题研究的几种常用方法的优缺点,提出了将非线性用户放入网络内,结合时域仿真评估其入网后对系统的影响和电能质量问题的研究方法。谐波源和电力负荷的建模对电能质量问题是比较重要的,本文总结了一些建模的理论方法和许多不同种类的模型,并应用于重要元件的仿真研究。目前对于谐波治理方面的理论主要包括主动治理和被动治理两大方面,但由于受到技术和成本的制约,并不是所有措施都能够真正得以应用于实际生产,本研究综合比较了多种电能质量谐波治理措施的特点及优劣,着重探讨通过设置无缘滤波器来治理谐波的技术,分别对谐波系统在滤波器设置前后系统的状态和谐波含量、电压、电流畸变率以及灵敏度等指标,验证了采用这种技术治理谐波的可行性。本研究引入了一种新型的仿真软件CYME对谐波网络进行模拟实验,该软件功能强大模型预定义库丰富,有专门开发的谐波分析模块方便研究。根据实际网络搭建系统仿真模型,对程序运行得到的谐波阻抗、电压、电流和灵敏度等指标加以分析,评估产生谐波的原因和谐波对系统电能质量的影响。搭建简单网络模型,仿真模拟其不存在谐波源和加入谐波源后的系统状况,并模拟了在系统内加入无源滤波器治理谐波的效果及其对系统带来的影响,结果表明这种谐波治理措施是符合实际需求的。本文从谐波评估和治理的角度进行了大量仿真实验,在实际生产中也可以用此研究手段对即将入网的非线性用户进行评估和规划。更多还原

【Abstract】 The rapid development of power systems provides a solid foundation for the improvement of power quality, the reliability and quality of electric power supply became hot issues recently. However, due to the existence of facilities with nonlinearity such as arc furnaces and electrified railways, harmonic problems in power systems are getting more serious. The harmonics in power system is not only a reason of voltage distortion, but also a contributing factor of the aggravation of power quality. Therefore, the harmonic content in public grid ought to be controlled within a certain range for safety and the normal operations of power systems. Power system is a integrated concept and related to a lot of aspects, so accurate prediction of the power quality problems before the facilities are put into use is feasible and highly in need. According to the prediction of relevant parameters, some solutions of harmonic problem can be given.Based on the national criterions about harmonic problems, harmonic evaluation and elimination are discussed in this research. A new theory of harmonic analysis and the elimination strategy are introduced in this essay. Modeling of harmonic sources and power load are very critical issues in harmonic research, in this research, some theories and methods on harmonics modeling and a variety of models are summarized and applied in the simulation of some important components in power system. Active and passive methods are two major strategies for harmonic elimination, but a lot of theories cannot be put into practical use because of the technology limitation and economical efficiency. Passive power filter is a mature and low-cost technology that can be taken into account in this research. The states of a harmonic system are indicated by parameters such as harmonics content, voltage, current distortion rate and sensitivity index.CYME is a suite of modular analysis programs with a common database and network editing facility. The suite includes programs for topics such as load flow, short circuit, harmonic and transient stability analyses of electrical networks. The highly interactive graphical interface makes it easy to simulate harmonic systems and get all the parameters needed in the research, so it is a very important part of the simulation. Based on practical harmonic system, parameters such as voltage, current, sensitivity index are detected by creating a network model in the graphical interface and running the software. The pre and post state of a harmonic system by setting power filters are given after the simulation, and the feasibility and economy of passive power filter in harmonic elimination are approved. This paper illustrates new methods of harmonics evaluation and elimination, it also can be applied in the practical production to evaluate and predict the construction of power system.更多还原