DETERMINATION OF ABNORMAL HARMONICS AND HARMONIC COMPOSITION COEFFICIENTS OF NON-SINUSOIDITY IN A 10 kV NETWORK WITH A VALVE ELECTRIC DRIVE OF DIRECT CURRENT

Autor: Evgen Khmelnуtskyi, Oleg Klyuyev
Rok vydání: 2023
Předmět:
Zdroj: Collection of scholarly papers of Dniprovsk State Technical University (Technical Sciences). 1:128-133
ISSN: 2617-8389
2519-2884
DOI: 10.31319/2519-2884.42.2023.15
Popis: The operation process of the electric valve drive is accompanied by the generation of higher harmonics — canonical and non-canonical. Limitation of the level of canonical harmonics is carried out by power resonance filters, however, in the case of asymmetry of the control pulses of the thyristors of the converters, non-canonical harmonics are generated — both even and odd harmonics. The composition of non-canonical harmonics can be determined in the case of harmonic analysis of non-sinusoidal current and voltage coefficients. The conducted harmonic analysis makes it possible to determine the composition of the filter-compensating device in the case of its design. The article examines the operation of a power supply unit with a powerful valve electric drive powered by controlled six-phase converters. Experimental measurement of higher harmonics showed the following: canonical harmonics ν £ 13 do not exceed 1—1.5 %, while the non-sinusoidal voltage coefficient exceeds the standard by 5 % (equal to 5.5—8.2 %). Such a situation is possible in the presence of high-order abnormal harmonics, which can be explained by the asymmetry of thyristor opening pulses e ³ 3 el. deg. This study is devoted to the analysis of the operation of the power supply unit with a powerful DC valve electric drive powered by controlled six-phase converters. Measurements showed an insignificant level of canonical harmonics (up to 1.5 %), while harmonics ν = 21—39 exceeded 2.5—3.5 %. Such a situation can be explained by the presence of abnormal harmonics of a high order, when the asymmetry of the opening pulses of the thyristors of the converters exceeds 3 el. deg. The analysis of the non-sinusoidal coefficients as a random process and its decomposition into a Fourier series made it possible to determine the harmonic composition of the current and voltage non-sinusoidal coefficients. Thus, the task of the research is defined in the calculation of the harmonic composition of non-sinusoidal coefficients and the analysis of abnormal harmonics
Databáze: OpenAIRE
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