Measuring method for equivalent system harmonic impedance of feeder line in power distribution network

Abstract

The invention discloses a measuring method for equivalent system harmonic impedance of a feeder line in a power distribution network. The method comprises the following steps: 10) obtaining harmonic test data and forming a harmonic data group; 20) carrying out data pre-processing: carrying out data pre-processing on the harmonic test data obtained in the step 10) to obtain harmonic difference data; 30) screening the harmonic data: screening a sample data group through a Nair detection method based on the harmonic difference data obtained in the step 20); and 40) calculating the equivalent system harmonic impedance: according to the ratio of standardized coefficients in the sample data, deleting abnormal data in harmonic voltage difference data, and calculating the equivalent system harmonic impedance by utilizing the retained harmonic voltage difference data. The method is targeted for the feeder line in a substation, can accurately calculate the equivalent system harmonic impedance value of the test feeder line, and is helpful for carrying out quantitative analysis on harmonic pollution caused by the feeder line to the system.

Description

technical field [0001] The invention belongs to the technical field of power quality monitoring and analysis, and specifically relates to a method for measuring the equivalent system harmonic impedance of a distribution network feeder. Background technique [0002] With the development of power electronic technology, various power electronic devices such as inverters, rectifiers and various switching power supplies are widely used. The switching action of these devices injects a large number of harmonic components into the grid, resulting in serious distortion of the voltage and current waveforms in the grid. At the same time, other nonlinear loads such as electric arc furnaces and electric welding machines in the power system have impact and unbalanced power consumption characteristics. While absorbing the fundamental power supplied by the system, they also convert part of the fundamental power into harmonic power and become the harmonic source of the power grid. Harmonic...

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Problems solved by technology

When the harmonic test is located on a certain feeder line, the background harmonics of the system side fluctuate greatly, and the use of the "non-intervention" method will lead to large errors in the harmonic impedance of the regression calculation, which will lead to inaccurate harmonic responsibility evaluation

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