Current Filtering in Three-Phase Three-Wire Power System at Asymmetric Sinusoidal Voltages

Abstract

Purpose. Investigation of the optimal current distribution between source, shunt active filter and reactive compensator of a three-phase three-wire system that provides consumption of a sinusoidal symmetric current under asymmetric source voltages with minimal power losses was provided. Methodology. The tasks were solved by conducting theoretical and experimental studies. The main provisions of the theory of electrical circuits, the apparatus of mathematical analysis, methods for solving linear differential and algebraic equations, elements of matrix and complex calculus and vector algebra are used. During the development, modern methods and software of computer simulation of electrical engineering complexes and dynamic systems were applied: Matlab-Simulink, MATHCAD. Originality. The principle of compensating current distribution between PAF and reactive compensator of a three-phase three-wire power system with asymmetric sinusoidal voltage was proposed at which the input current is equal to the positive-sequence active current and rms value of PAF current is minimal. The feasibility to compensate the inactive sinusoidal Fryze current by reactive elements under arbitrary combination of load and source parameters was proved and expression for direct calculation of the reactive compensator parameters for generation of inactive Fryze current in the source unbalanced mode was obtained. Practical value. The simulative example for transmission line load showed that combined application of PAF and reactive compensator with the specified distribution of compensating currents ensured a reduction of power losses in 3.273 times and rms value of the SAF current is 12.9 % of rms value total compensation current. References 10, tables 1, figures 2. Key words: active and inactive Fryze current, asymmetrical voltage and load, reactive compensator, symmetrical components. Рассмотрены принципы активной фильтрации тока в трехфазной трехпроводной системе электропитания при несимметричном синусоидальном источнике питания, удовлетворяющие требованиям стандарта IEEE Std.1459-2010. Показаны преимущества формирования синусоидального симметричного входного тока при параллельном подключении активного фильтра и реактивного компенсатора. Доказана возможность компенсации неактивного синусоидального тока Фризе реактивными элементами при произвольной комбинации параметров нагрузки и источника. Получена формула прямого расчета параметров реактивного компенсатора для генерации неактивного тока Фризе в несимметричном режиме источника питания. Приводятся результаты численного моделирования. Библ. 10, табл. 1, рис. 2. Ключевые слова: активный и неактивный ток Фризе, несимметричное напряжение и нагрузка, реактивный компенсатор, симметричные составляющие.