Power Harmonics Detection And Analysis Method

With the progress of science and technology, various kinds of new electrical equipment are being widely used in all aspects of society. The high safety and high precision during the operation of these equipment correspondingly requires even higher standards in the use and demand for electricity. However, the extensive use of non-linear load has brought about severe power harmonics pollution, deeply impacting the safe, stable and efficient operation of the system and power-supply and the electronic equipment. How to minimize the damage of harmonics is an issue of great concern to the field of power systems. The key to solution of this issue lies in the quantitative determination of the composition, magnitude and phases of harmonious waves. It is vital to improve the monitoring and analysis of harmonious wave in the electric network in order to inhibit the high-frequency harmonious wave.This paper first of all made a review and prospective study of the detection and analysis approaches of the harmonious wave both in China and abroad, specified the basic concepts and characteristic parameters of power harmonics, and discussed the generation of harmonics in the terms of power generation, electricity transmission, electricity utility. The harmonic harm was described in terms of following aspects: the increase of additional supplementary load loss of transmission, distributed equipments and electrical installations; the influence on measurement meter, the operation reliability of relaying protection and automatic devices as well as the use and life span of household electrical appliances. The harmonic detection and analysis method based on Frayzer transformation and instantaneous reactive power theory was described detailedly. By comparison, it is showed that the method based on instantaneous reactive power theory had good real time and small retardation time, and to be able to detect the harmonic and compensate the reactive power. However, the method based on fast Frayzer transformation was used widely in harmonic detection, reactive power compensation and frequency and spectral analysis. But the fast Frayzer transformation algorithm adopted in the practical application had inevitable grid effect and frequency spectrum leakage, leading to larger error and worse real time in harmonic detection. Then, the methods of harmonic suppression in power system were described in the following aspects: carrying out strictly the national standard of harmonics, and strengthening the monitoring of the source of harmonics pollution; installing the filtering device to absorb the current of the harmonious wave, installing the static reactive power compensation equipments to improve the power factor; preventing the amplification of harmonic because of shunt capacitor bank;...