摘要
随着电力电子设备数量的迅速增多和电网中各种非线性负载的增加,电网电压、电流中的谐波含量日益增高,致使供电和用电设备过热、电能损耗增加,、对电力系统的安全、经济运行造成极大影响。实时测量电网中的谐波含量,对于防止谐波危害具有重要的现实意义。
为了实现对电网中的谐波实时而精确的检测,首先对文献和专著中给出的各种谐波检测方法进行了分析和比较,确定了谐波检测所采用的算法,并在此基础上完成一种谐波检测仪整体方案的设计。该检测仪可以完成对三路输入信号的电压、电流的谐波含量进行检测,并配备了对检测数据进行显示、统计和存储的功能。
论文介绍了电力系统谐波检测仪的研究设计过程,并分别从谐波算法的研究选择、系统硬件设计、系统软件设计、系统测试等方面加以论述。本文具体内容如下:首先介绍了谐波检测研究的意义、谐波的危害及谐波检测现状。然后介绍了谐波的概念、谐波检测的方法,并在对几种谐波检测算法分析研究的基础上,确定了本谐波检测仪所采用的基于快速傅立叶变换的加窗插值算法。第三部分叙述了以ARM7为微处理器的检测仪系统硬件设计,包括主控模块、信号调理模块、A/D采样模块、数据存储模块、实时时钟模块、液晶显示模块的设计和硬件抗干扰设计等工作。第四部分是谐波检测仪系统软件的设计。介绍了利用C语言开发的系统软件,包括主程序、A/D转换、按键处理、数据处理等组成部分。之后是系统测试与误差分析部分,经过对实测信号结果的分析,证明算法的选择与检测仪的设计满足精度要求。最后是对以上研究工作进行的总结,并对未来工作进行了展望。
Along with the rapid increase of both power electronic devices and nonlinear loads in power systems, the harmonic components in power system voltage and current increasingly ascend, it makes power supply equipments and power utilization equipments overheating, power loss ascending, and evidently affects the secure, economic and stable operation of power system. Thus, it is of practical significance in the prevention of the harm from harmonics to measure harmonic contents in power system voltage and current in power system by real-time ways.
To implement the real-time and accurate detection of harmonics in power system, firstly, the author compared and analyzed the existing harmonic detection methods published in periodicals and treatises; then the algorithm to be used for harmonic detection was decided; on this basis the design of a whole scheme of harmonic detector was finished. With the designed harmonic detector the harmonic contents existing in input voltage and current signals from three channels can be detected simultaneously, and the functions such as the display, statistics and storage of the detected data were equipped in this detector.
In this paper, the research and design of a power system harmonic detector is presented. The study and selection of harmonic algorithm, the design of hardware and software system as well as the test of detection system are discoursed upon respectively. The concrete contents of this paper are as following:in the first part of this paper, the significance of the research on harmonic detection, the danger in power system caused by harmonics and the present situation of harmonic detection were expounded; in the second part, the concept of harmonics, the methods of harmonics detection were presented, and on the basis of analysis and research on several harmonic detection algorithms a fast Fourier transform (FFT) based windowed interpolation algorithm applied in the designed harmonic detector was determined; in the third part, the hardware design of this harmonic detection system was described, in which the advanced RISC machine (ARM) chip ARM7 was adopted as microprocessor and the design of such modules as main control, signal modulating, A/D sampling, data storage, real-time clock and liquid crystal display (LCD), as well as the anti-interference design for hardware were included; in the fourth part, the design of software for this harmonic detector was given, the system software consists of main program, analog-digital conversion, key processing and data processing, and the software was programmed by C language; the system test and error analysis were brought into the fifth part, after the analysis on the measured signals it was proved that both algorithm selection and the design of the detector can meet the requirement of accuracy; finally, above-mentioned research and design are summarized and the work to be carried out in the future was pointed out.
引文
1.王兆安.谐波抑制和无功功率补偿[M],北京:机械工业出版社,1998:1-2
2.付周兴,赵永秀.电网谐波测量技术的现状与发展[J],工矿自动化,2004,(2):17-19
3.尹婧.电力系统谐波的危害及治理[J],武汉船舶职业技术学院学报,2004,(1):19-21
4.曲学基.谐波分析与抑制[J],技术研究,2007,76(10):31-33
5.汉泽西,姚英彪.用DFT分析正弦信号频谱时应注意的几个问题[J],西安石油学院学报(自然科学版),2003,18(2):67-70
6.陈其松,陈孝威,戚琳,王国美.电力系统谐波检测与抑制[J],微计算机信息(测控自动化),2007,23(10):258-259
7.Ranatunga R A, Annakkage U D, Kumble C S. Algorithms for incorporating reactive Power intomarket dispatch[J], Electric Power System Research,2003(65):179-186
8.Gerard L Doorman, Nygreen B.An integrated model for market pricing of energy and ancillary services[J], Electric Power Systems Research,2002(61):169-177
9.Jain V K, Collins W L, Davis D C.High—accuracy analog measurements via interpolated FFT[J], IEEE Trans on Instrum Meas,1979,28(2):113-122
10.李晓竹,赵毅.基于电量采集装置的FFT算法研究[J],科技咨询导报,2007,(28):45
11.余晓明,吴捷,王世闻,张勇.基于DSP的通用FFT算法在电网谐波检测中的应用[J],北京联合大学学报(自然科学版),2007,21(3):28-31
12.Ribeiro P F.Wavelet. Transform:Advanced Tool for Analyzing Non-Stationary Harmonic Distortions in Power Systems[J],Proceeding of IEEE ICHPS VI.Bologna,1994:365-369
13.Jain v K, Collins W L, Davis D C.High—accuracy analog measurements via interpolated FFT[J],IEEE Trans IM,1979(28):112-13
14.田秀华,王忠宝,张展.基于连续傅里叶变换计算离散傅里叶变换的一种算法[J],自动化技术与应用,2007,26(8):34-35
15.殷庆平,牛晓平.电力系统谐波测量中频谱泄漏问题的研究[J],工矿自动化,2007(8):28-29
16.毛青春,徐分亮.窗函数及其应用[J],中国水运,2007,7(2):230-232
17.裴亮,李晶,郭发东,刘雷,胡军锋.电力系统谐波分析中Hanning窗插值算法的应用[J],山东科学,2005,18(5):76-79
18.Andria G, Savino M, Trotta A. Windows and interpolation algorithms to improve electrical measurement accuracy[J], IEEE Tans IM,1989,38(4):856-863
19.杨艳娟,窗函数的适用性分析[J],煤炭技术,2007,26(2):124-125
20.易立强,邝继顺,欧阳雄.基于一类新窗的高精度相位差测量方法[J],系统仿真学报,2007,19(23):5543-5545
21.Contreras J, Conejo A Jdela TorreSet al.Power engineering lab.electricity market simulator [J], IEEE Transactions on Power Systems,2002,17(2):223-228
22.黄纯,江亚群.谐波分析的加窗插值改进算法,中国电机工程学报[J],2005,25(15):26-29
23.蔡晓燕.电网谐波分析的加窗插值算法[J],仿真科技广场,2007,(7):210-212
24.Grandke T. Interpolation algorithms for discrete Fourier transform of weighed signals[J], IEEE Trans on Instrum Meas,1983,32,(2):350-355
25.Harris F J.On the use of windows for harmonic analysis m the discrete Fourier transform[J], Proc IEEE,1978,66,(1):51-83
26.Rife D C,Vincent G A. Use of the discrete Fourier transform in the measurement of frequencies and levels of tones[J], The Bell System Technical Journal,1970,(1):197-228
27.陈明军,毛樟梅.改进窗函数在FIR数字滤波器设计中的应用[J],继电器,2007,7(35):65-67
28.翟洪叶,符影杰.基于ARM的电网电压谐波监测仪的研制[J],中国仪器仪表,2006,(10):33-35
29.周立功,张华.深入浅出ARM7-LPC213X/214X(上册)[M],北京:北京航空航天大学出版社,2005:51-122
30.潘焕成,赵卫东.新型A/D变换器AD73360及其应用[J],国内外电子元器件,2002,(4):53-55
31.李海鸿,朱元清,陈蓓.实时时钟芯片PCF8563及其应用[J],国外电子测量技术,2002,(5):29-31
32.王幸之.单片机应用系统抗干扰技术[M],北京:北京航空航天大学出版社,2000:28-50
33.王飞.基于DSP技术的电力谐波监测仪的研制[D],广东工业大学,2004
34.范婕.基于DSP的谐波测量仪研究[D],华中科技大学,2006,28-50