Method for identifying types of harmonic sources on basis of characteristic quantity analysis

Abstract

The invention discloses a method for identifying the types of harmonic sources on the basis of characteristic quantity analysis. The method comprises the following steps that firstly, voltage and current data of all branch loads are collected, fast Fourier analysis is conducted through data processing and operating, fundamental waves and each harmonic component of the voltage and current of each branch are obtained, three characteristic quantities of a crest factor (CF), a form factor (FF) and current total harmonic distortion (THDI) are obtained through calculation, and whether the branch loads are the harmonic sources or not is judged according to the standard IEEE519 and the national standard GBT24337-2009; the harmonic sources are classified, whether the harmonic sources belong to the ferromagnetic saturation type or the electronic power switch type or the electric arc type or one of other types not including the ferromagnetic saturation type, the electronic power switch type and the electric arc type is judged. The method has the advantages that the method is fast and accurate, the characteristic quantities are simply and conveniently used for qualitatively analyzing the types of the harmonic sources, the method can be used for identifying the type of each harmonic source of the distribution network, and therefore a basis is provided for targeted harmonic control of a system.

Description

technical field [0001] The invention relates to a method for identifying the type of a harmonic source based on feature quantity analysis, and belongs to the field of harmonic analysis of electric power systems. Background technique [0002] Harmonic source identification technology is an important branch in the field of harmonic research. It is the premise of harmonic control for the system and the basis for harmonic responsibility sharing between the system and users. With the continuous development of the power system, various non- More and more linear loads are connected to the grid, and a large number of harmonics are injected into the grid, which damages the power quality of the power supply system. At present, the methods for identifying harmonic sources mainly include active power method, load parameter identification method, critical impedance method and so on. Among them, the active power method uses the sign of the harmonic active power to identify the position...

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Problems solved by technology

Among them, the active power method uses the sign of the harmonic active power to identify the position of the harmonic source, but because it is easily affected by the power angle, this method is prone to misjudgment and failure; the load parameter identification method relies on the degree of nonlinearity of R or L Quantitative analysis, this method can better analyze and predict the behavior characteristics of the distribution system under the influence of harmonics, and to a certain extent can be used as a criterion for judging the degree of user load distortion, but the rationality of the judgment method and its results are not The method of judging the degree of linearity still needs to be studied and verified, and further discussion is needed in practical applications; the critical impedance method is judged from the flow direction of reactive power, so as to locate harmonics. In actual use, this method still needs to predict the approximate Impedance information is used to start the algorithm, and the harmonic impedance characteristics are considered to be the same everywhere in the system, which will bring large errors in practical applications

[0003] In short, although the identification of harmonic sources is very important at home and abroad, the existing methods are still subject to certain restrictions in application, and the results obtained in practical applications are not very ideal. In fact, the identification of harmonic sources is only a Qualitative questions, only need to use simple qualitative indicators to achieve the goal

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