电力系统谐波成因分析及谐波潮流计算外文翻译.doc

1、Analysis of power system overtone and overtone tidal current to calculateFirst, introduction an ideal electrical power system is by the sole constant frequency and the stipulation peak-to-peak value regulated voltage power supply. But in fact, as a result of the recent years along with sciences and

2、technologys unceasing development, the high efficiency traded the class equipment and the modulator use, high in the electrical power system presses the nonlinear element which the direct current transmission the application, the massive misalignment loads appearance as well as the power supply syst

3、em itself existed and so on to cause in the systems voltage waveform distortion to be getting more and more serious, has caused the very big harm to the electrical power system, for example: Causes in the power supply system the part to lose increases, reduces current collectors service life, to dis

4、turb the communication system and so on. Serious when even can also cause equipment the damage, automatic control malfunction, relay protection misoperation, thus creates the power cut accident and so on and other questions. So-called the friend knows other, is undefeated in many battles , therefore

5、, must realize to the electrical network overtone comprehensive program of public order, must make clear the overtone origin and the electrical network in under the each different movement way the overtone tidal current distributed situation, adopts the corresponding measure limit and the harmonic c

6、ancellation, thus changes the friendly power supply system power supply quality and guarantees systems security economy movement. Second, electrical power system overtones origin in the electrical power system the overtone source is many and varied. Mainly has the following several kinds: in 1, syst

7、ems each kind of misalignment current collector for example: Trades the class equipment, the modulator, the electrification railroad, the arc furnace, fluorescence the lamp, the domestic electric appliances as well as each kind of electronic energy conservation control device and so on is the electr

8、ical power system overtone important source. Even if these equipment supplies its ideal sine wave voltage, it uses the electric current is also non-linear, namely has the harmonic current existence. And these the equipment produces the harmonic current will also pour into the electrical power system

9、, will cause system each place voltage to have the harmonic component. These equipments harmony the wave content decided that in its characteristic and the working condition, basically has nothing to do with the electrical power system parameter, may regard as overtone constant flow the source. 2, t

10、he power supply system itself exists the nonlinear element is overtone another origin. These nonlinear element mainly has the transformer to stir up the capacitor which, the reactor group the magnetism leg, the alternating and direct convertor stations silicon-controlled rectifier controlling elemen

11、t, the silicon-controlled rectifier control and so on. 3rd, like the fluorescent lamp, the domestic electric appliances and so on single capacity is not big, but quantity and spreads very greatly in each place, electric power department with difficulty management current collector. If these equipmen

12、ts current harmonics content is oversized, will then have the serious influence to the electrical power system, to this kind of equipments current harmonics content, when manufacture namely should limit in certain quantity scope. 4, the generator send out overtone electric potential. The generator w

13、ill send out the overtone electric potential at the same time also to have the overtone electric potential production, its overtone electricity the potential will be decided by generators structure and the working condition, basically will have nothing to do with the external connection impedance. T

14、herefore may regard as overtone constant pressure source , but its value is very small.the three, electrical power system overtone tidal current calculates the so-called electrical power system overtone tidal current computation, is through solution network equation In=YnUn (n=3,5,7 . n: Agrees wave

15、 number the number. In is the overtone source load pours into electrical networks n subharmonic electric current row vector. Yn is electrical networks n subharmonic conductance. Un is in the electrical network a various nodes bus bar n subharmonic voltage row vector). Obtains in the electrical netwo

16、rk various nodes (bus bar) the harmonic voltage, enters to obtain in various legs harmonic current. When in the electrical power system the existence has the overtone source, this time in the system the contact voltage and the branch current will have the higher harmonic. For the determination harmonic voltage and harmonic currents in power supply system distribution, needed to carry on to the overtone impedance constitution equivalent circuit the tidal current