Method for recognizing harmonic source in electric power distribution network

Abstract

The invention relates to a harmonic source identification method of a power distribution network, which belongs to the technical field of electric power and is used to solve the harmonic source identification problem. The technical proposal comprises calculating load resistance parameter, electric inductance parameter or capacitance parameter reciprocal sequence value and the average value of load resistance parameter, electric inductance parameter or capacitance parameter reciprocal sequence value along with the change of sampling time according to common point voltage and load branch electric current which are actually measured, and reversely calculating electrified wire netting linear load voltage according to the average value of load branch current and resistance parameter, electric inductance parameter or capacitance parameter reciprocal sequence value, then calculating non-linear quantizing factor of n difference sequences of linear load voltage which is calculated with common point voltage, finally comparing non-linear quantizing factor with empirical threshold value to judge whether load is harmonic source load or not. The invention not only judges accurately and reliably, but also can not be limited by other factors, which can identify the harmonic source under any conditions.

Description

technical field [0001] The invention relates to a method capable of identifying harmonic pollution in a power distribution network, which belongs to the technical field of electric power. Background technique [0002] With the wide application of power electronic technology in electrical equipment and the continuous increase of other nonlinear loads, the problem of harmonic pollution in power distribution networks has become increasingly serious, which has endangered the safety and economic operation of power grids and electrical equipment itself. For this reason, the analysis and comprehensive treatment of harmonic problems have become a subject of widespread concern at home and abroad. Correctly identifying the harmonic source and estimating the amount of harmonic injection are the primary issues in the field of harmonic analysis and governance, and are of great significance to solving the contradiction between the power supply side and the user side caused by harmonic pol...

AI Technical Summary

Problems solved by technology

However, this method is affected by the phase angle difference on both sides of the common connection point, and often cannot correctly identify the harmonic source in the case of multiple harmonic sources

The superposition method is obtained on the premise that the reference harmonic impedance of the system side and the user side is known, but it is difficult to obtain the reference harmonic impedance in practical applications, and this method is subject to certain restrictions in practical applications

Since the active power of the power system is mainly related to the phase angle, while the reactive power mainly depends on the magnitude of the system voltage, the method based on reactive power can only be judged correctly when the reactive power Q>0, and when Q<0, then Can't judge

The critical impedance method needs to estimate the harmonic impedance values ​​of the system and the user side, and considers that the harmonic impedance is evenly distributed in the system. Because the load fluctuation of the actual power system is relatively large, the harmonic impedance is measured under the condition of disturbance. The disturbance is random and unstable, and the method is limited in practical application

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