【作者】 程汉湘；

【导师】 尹项根；

【作者基本信息】 华中科技大学 ， 电力系统及其自动化， 2004， 博士

【摘要】 本论文针对电力系统中配电系统StatCom展开论述,它要解决的主要任务是输入端电压的稳定和无功功率的补偿,并对具有特殊性质的负荷特性实现动态补偿,使之能够解决象油田抽油机这类负载的动态要求。进一步还应该完成有源滤波器的消除谐波的任务。而前面几点则是本论文要阐述的重点。使用StatCom的目的是为了解决日益增加的电力用户和资源有限的电网容量之间存在的矛盾,同时还解决电力系统中由于使用了大量非线性的新型器件和其它原因所产生的电能质量问题。StatCom以及其它的FACTS装置在电力系统的潮流控制和电能质量控制中,已被证明是非常有效的,而且也是经济实用的,它们已经或者正在取代传统的电力系统设备,在电能的生产、传输和使用的各个环节中都发挥着重要作用。论文首先对FACTS技术的发展历史、概况、以及它的作用作了一个简单介绍。除了StatCom外,文中还简要介绍了FACTS中几个其它常用控制器的基本原理,以及它们之间的结构和原理上的区别。根据国际标准,文中对于像“电能质量”这样颇为模糊的概念给出了详细的解释,罗列了国际上重要的FACTS应用实例,特别是对StatCom装置的使用情况作了尽可能详细的介绍。该部分反映了国际上在该研究领域的最新研究进展。文中在讨论StatCom实现无功补偿的原理以及电压稳定的基本概念的基础上,明确提出了输电系统的StatCom以及配电系统的StatCom是两个不同的概念。一般来讲,输电系统StatCom的输出电压等级和补偿容量都要高于配电系统的电压等级,但配电系统StatCom除了要发挥一般StatCom的通用作用外,它还必须能消除负载所造成的谐波污染,并要求对负载的快速波动做出迅速反应。因此,它们的控制目标有相同点,也有不同点。为了保证配电系统的StatCom能够正常发挥其作用,了解控制参数和系统参数对控制特性产生的影响是非常重要的。本文描述和分析了这些参数与StatCom稳态运行特性之间的关系,同时给出了参数选择的思路。作为实际应用来讲,StatCom的动、稳态特性是非常重要的。文中对具有高动态特性的StatCom的工作原理及暂态过程进行了理论方面的研究和探讨,特别是对两电平和双三点式的典型结构进行了分析,在此基础之上,提出了电压内嵌式的控制策略。从控制策略的研究上看,有很多种方法,虽然它们要实现的目标是一致的,但电压内<WP=4>嵌式控制策略与通常由电流、电压所构成的双闭环控制系统有很大的不同,当然也与逆变器常用的虚拟磁通控制和其它形式的控制策略都有很大的区别。这种电压内嵌式控制策略将电压环放在内环,而将无功控制环放在外环。由于电压环处于内环,可以快速调节端点电压,保证电压的稳定;无功环放在外环可以保证总体控制目标能够进行无功补偿,但速度可以慢一点。通过仿真研究结果表明,当负载无功发生突变时,端点电压可以在20ms内达到稳定,无功功率则可在3个周波内达到整定值。在StatCom的研究中,直流电容参数是难于处理的问题,特别是在不同电路结构情况下。对于电压源型结构来讲,直流电容的选择一般都采用较为模糊的参数确定方法,比较保守,通常是偏大,这样既不经济,体积也太大。本文从电路结构的数学模型出发,对典型结构的参数选择进行了详细分析,提出了根据系统结构特征值、直流电压动态波形曲线和电场能量变化率这三种电容参数确定方法和对应的计算公式。将StatCom用于油田抽油机的节能是FACTS应用的又一个重要领域,文中对其应用的实现原理和稳定性进行了详细的分析,叙述了如何将StatCom用于抽油机的节能之中,总结了几种不同节能方法的优缺点,提出了解决该问题的实现方案,同时给出了在给定参数情况下的大量仿真分析,并得出了在保证功率因数、稳定节电压的前提下的稳定性参数选择范围。尽管现有的稳定性分析方法中,很少涉及到FACTS存在时的电力系统稳定性研究内容,但本文在传统的时域分析法的基础上,增加了并联型StatCom的稳定性分析。文中强调了在单机-无穷大系统模型及有关给定系统参数下,实现系统稳定运行的基本原理,这应该说是对电力系统稳定分析的一个重要补充。从仿真的研究结果中可以看出,用StatCom是完全可以实现抽油机的电机节能,它的动态性能也完全能满足抽油机负载特性的变化要求,其功率因数至少可以提高到0.93以上。影响节能效益的主要因数与系统参数有关,它会影响补偿装置的动态响应速度。总之,StatCom的控制和运行与很多因素有关,要能充分发挥它的作用还有很多的问题要澄清,特别是在系统动态过程中的物理概念,以及相关控制输出作用后对功率元件的冲击等,都还有待于进一步研究,FACTS对系统稳定性的影响还应该有一个更为深入地了解,稳定性模型的合理简化等。作者希望,通过本文的介绍能够使有关专业人员或学者对StatCom的认识有一定的帮助,并对他们今后的研究工作有所启迪,或者是借鉴作用。如能达到这一点,作者将甚为欣慰。更多还原

【Abstract】 This paper described the StatCom of distribution to power systems. The typical objects of distribution StatCom are node-voltage stability, reactive power compensation, dynamic characteristics for special loads, such as oil-pump motor in oil-field, in addition, harmonics reduction. The first two or three objects are main points described in this paper. StatCom applications in power systems is an attempt to solve the conflict between daily increased power consumers and the finite source of power networks, at the mean time, to solve power quality problems caused by a large number of nonlinear new power equipments and other reasons. The effect of StatCom or other FACTS controller has been proved successfully. It shows also very economically and practically. FACTS have replaced, or are replacing traditional power facilities, and plays important role in power transmission, distribution and power usages. At the first, it describes the history, survey, and the functions of FACTS in this paper. Besides StatCom, the basic working principles of other common FACTS controllers and theirs differences between configuration and corresponding theories are also expressed. Detail explanation for obscure term, such as concept of “power quality”, has been made in accordance to international standards; the famous practices of important FACTS in the word, especially the StatCom, are enumerated with explanation as detailed as possible. In fact, it has presented the latest development in the research field of FACTS in this part. The fundament principle of compensation and voltage stability with StatCom are described in this paper. The StatCom terminologies of transmission and distribution systems are clearly expressed for the first time in this paper. Normally speaking, the voltage level and compensation capacity of transmission StatCom is higher than that of distribution StatCom; but the distribution StatCom should reduce harmonic pollution produced by load besides its normal functions, and it should respond quick enough while the harmonic and reactive power variation caused by load vary sharply under operation. There are some common control objects to both StatCom, and there are also some distinctive to each other. To be familiar with the control and system parameters to distribution systems is very important in order to complete normal function for distribution StatCom. The relationship between parameter’s variation and operation characteristics of StatCom is described; some <WP=6>suggestions for the proper selection of parameters are proposed at mean time.Practically speaking, the dynamic and steady state characteristics of StatCom are very important. The research and analysis of the operation principal and dynamic process for StatCom have been made, especially for the typical configurations of two-level and dual three-point inverter. The control strategy inner-nested with DC-link voltage is proposed in this paper. From the view of control strategy, although there are many other control strategies used for StatCom control, which have some same control objects also with each other, it presents some distinctive compared with dual-loop feed-back control strategy formed with line current and voltage, it has difference with so-called virtual-flux control and other control strategies also. In the control strategy, voltage control loop is in inloop, whereas the reactive power loop is in outloop, so it can regulate node voltage very quickly, and control reactive power with relative more time, but the two objects mentioned above can be realized overall. The simulation results indicate that the node-voltage could enter steady state within 20ms, and reactive power in 3 periods, when there is a prompt disturb of load reactive power.The parameter selection to DC-link is difficult to deal with in the StatCom research, especially with different circuit configurations. The DC capacitor for voltage-sourced inverter (VSI) is normally conservatively selected, it leads to higher capacity, larger volume, and not economical. Derived from the math更多还原