IMITATION MODELING OF THE HYBRID VAR COMPENSATOR
O.S. Savenko, Svetlana Podnebennaya, Володимир Володимирович Бурлака · Electrical Engineering and Power Engineering · 2019
Purpose. Study of the effectiveness of the hybrid VAR compensator, which consists of series-connected capacitor bank (CB) with discrete regulation and active filter of higher harmonics, with different control strategies, under asymmetrical and / or non-sinusoidal grid voltage and loads, in a graphical programming environment Matlab Simulink.Methodology. Methods of electrical engineering, numerical modeling methods, methods of the theory of coordinate systems transformation, methods of matrix transformations.Findings. Several control strategies for hybrid VAR compensator are considered: operating in the mode of reactive power compensation with isolation of CB from higher harmonics; working in the mode of active filtering (AF) of higher harmonics. To calculate the required capacitance of the CB and the reference current of AF, the instantaneous power theory (p-q theory) and d-q theory on the fundamental frequency are considered. The effectiveness check of the considered control strategies was performed in the graphical programming environment Matlab Simulink. Simulation models that allow a qualitative assessment of the effectiveness of the hybrid VAR compensator work with various control strategies have been synthesized. It has been established that, under the conditions of asymmetry and / or non-sinusoidality of the grid voltage, it is advisable to synthesize the control system for the compensator using the d-q theory for the fundamental frequency. In the process of modeling, it has been established that the proposed hybrid VAR compensator allows the smooth regulation of reactive power, while the AF power is not more than 10% of the total VAR compensator power (for given simulation parameters). When operating in the filtering of higher harmonics mode, the VAR compensator also showed high efficiency, the AF power was not more than 20% of the total compensator power. To illustrate the effectiveness of the approach, the diagrams of currents and voltages are given, Total Harmonic Distortion (THDI) and the power factor of the complex «VAR compensator + nonlinear load» are calculated.Originality. The control method for VAR compensator was further developed. It consists in the joint control of CB with discrete regulation and AF: 1) according to the condition of reactive power compensation and «isolation» of CB from higher harmonics; 2) according to the condition of compensation of higher harmonics of the current (working in the parallel active filter mode).Practical value. A simulation model of a hybrid reactive power compensator has been developed, which implements several control strategies. The operation of the compensator was checked under asymmetrical and / or non-sinusoidal grid voltage. The effectiveness of the proposed approach is confirmed.