Enhancement of Power Quality using Tapped Inductor FC-TCR

This Paper deals with digital simulation of FC-TCR, which can enhance the Power Quality of a power system. Reactive power is controlled by using tapped inductor system. This system reduces THD in the line current. Smooth variation of reactive power can be obtained by varying the firing angle of TCR. This circuit eliminates switching transients and improves the life of the capacitors. The simulation was performed using MATLAB Simulink and the simulation results are presented. The simulation results are similar to the analytical results. Introduction In the control of electric power systems, systems and procedures are used to compensate dynamically the detrimental effects of non-linear loads. The compensation process should be carried out without important alteration of the source signals quality. Some benefits are expected using compensation losses reduction in the distribution lines, harmonic content aminoration, and power factor improvement. The dynamic behavior of industrial loads requires the use of compensator that can be adopted to load changes. Unfortunately, the techniques frequently used for Compensation is based on circuit controllers that alter the waveform of the signals subject to the control. Such is the case of the static compensator, which must perform harmonic cancellation, reactive power compensation, power factor correction, and energy saving. Although the static compensator is commonly used and studied under sinusoidal voltage conditions, waveforms corresponding to the controlled current present high harmonic content. This paper focuses on the Thyristor-Controlled Reactor (TCR). The compensator with TCR controls the current in the reactor L from a maximum (Thyristor valve T closed) to zero (Thyristor valve T open) by the method of firing delay angle control. The fixed capacitor (FC) and the TCR constitute a basic var generator arrangement (FC-TCR). The constant capacitive var generation of C is opposed by the variable var absorption of the TCR. Calculation of the firing angle can be made in the time domain or in the frequency domain, using different approaches. Assuming the supply voltage is sinusoidal, calculation of the firing angle is obtained with minimum complexity. However, the modification of TCR firing angle, increasing from limits � = 0 to ��= , 2 � produces increasing distortion of the current in the TCR branch, and consequently that of the line current. It increases the rms value of the line current and the THD, and deteriorates the power factor. This situation is still more degraded where voltage is not a pure sine wave. In the literature [1] to [20], the simulation of tapped FC-TCR is not presented. In the present work, an attempt is made to simulate Tapped FC-TCR system using MATLAB Simulink software.