Analysis of non-sinusoidal modes of operation of electrical equipment in power supply systems with semiconductor converters

Abstract

Introduction. With the increasing number of electrical loads with non-linear volt-ampere characteristic, there are problems with distortion of the shape of the supply voltage and current curve. These distortions can lead to undesirable effects such as network overload, harmonic distortion, unacceptable voltage and current ripple, etc. Goal. To investigate non-sinusoidal modes of operation of electrical equipment in the power supply system to predict the quality of electrical energy and develop measures to ensure electromagnetic compatibility of electrical equipment in power supply systems. Materials and methods. The simulation model developed in MATLAB/Simulink software complex allows to analyze the operation of the power supply system with semiconductor converters under different conditions and predict its behaviour under different loads and external influences. Results and discussion. In the course of work it was found that in the absence of reactive power compensation devices, the levels of the total coefficient of higher harmonic components of voltage KU(n), in the power supply system with 12-pulse converter exceed the permissible values during 95% of the measurement interval time in accordance with GOST 32144-2013 (in the connection points of 6 kV). The values of the coefficient of the n-th harmonic component of voltage at 11, 13, 23, 25, 35 37 harmonics in some cases exceed the permissible values during 100% of the measurement interval time. When using compensation means (batteries of static capacitors, resonant filter), the values of the total coefficients of voltage harmonic components do not exceed the permissible values. Conclusion. According to the results of the study, it is clear that the widespread use of rectifier devices leads to a significant distortion of the voltage curve. However, it should be noted that the existing GOST regulates only the value of harmonic components of voltage and does not take into account the harmonic components of current, which in turn also have a detrimental effect on the elements of the electrical network.

Keywords

• simulation
• power supply systems
• non-sinusoidal modes
• current and voltage harmonics
• semiconductor converters