A Multifunctional Dynamic Voltage Restorer for Power Quality Improvement

Abstract

Power quality is a major concern in electrical power systems. The power quality disturbances such as sags, swells, harmonic distortion and other interruptions have an impact on the electrical devices and machines and in severe cases can cause serious damages. Therefore it is necessary to recognize and compensate all types of disturbances at an earliest time to ensure normal and efficient operation of the power system. To solve these problems, many types of power devices are used. At the present time, one of those devices, Dynamic Voltage Restorer (DVR) is the most efficient and effective device used in power distribution systems. In this paper, design and modeling of a new structure and a new control method of multifunctional DVRs for voltage quality correction are presented. The new control method was built in the stationary frame by combining Proportional Resonant controllers and Sequence-Decouple Resonant controllers. The performance of the device and this method under different conditions such as voltage swell, voltage sag due to symmetrical and unsymmetrical short circuit, starting of motors, and voltage distortion are described. Simulation result show the superior capability of the proposed DVR to improve power quality under different operating conditions and the effectiveness of the proposed method. The proposed new DVR controller is able to detect the voltage disturbances and control the converter to inject appropriate voltages independently for each phase and compensate to load voltage through three single-phase transformers.

Two-Feeder Dynamic Voltage Restorer for Application in Custom Power Parks

“…Both generated the corresponding injection voltage to compensate for the swell. The injection voltage of the DVR presented in [27] presented a slight distortion when the disturbance occurred. On the other hand, the injection voltage generated by the proposed DVR showed a voltage spike.…”

“…In order to compare the performance between the proposed two-input DVR and a one-input DVR in sags compensation, consider Figures 10 and Figure 13 taken from [27]. At the beginning of the sag, the proposed two-input DVR ( Figure 10) responded quickly, and the load voltage showed a slight flicker.…”

“…On the other hand, the injection voltage generated by the proposed DVR showed a voltage spike. The waveforms of Figure 17a show a spike in the load voltage when the Figure 14 and Figure 17a (Taken from [27]) show the waveforms of the proposed two-input DVR and the DVR presented in [27] in the compensation of a swell. The two DVRs responded immediately when the disturbance occurred.…”

“…The simulation results presented in Figures 14d and 15c show the effectiveness of the proposed DVR in maintaining invariant load voltages and currents despite the presence of voltage swells in the critical grid. Figures 14 and 17a (Taken from [27]) show the waveforms of the proposed two-input DVR and the DVR presented in [27] in the compensation of a swell. The two DVRs responded immediately when the disturbance occurred.…”

“…However, DVRs have also been used to compensate for voltage harmonics [23][24][25], swells [25] and unbalanced sags [25,26]. In [27] a multifunctional DVR was proposed, one capable of compensating balanced and unbalanced sags and swells, fluctuations and voltage distortion and voltage sags due to starting of a motor. In contrast, the proposed two-input DVR extends its compensation capacity to several voltage disturbances: Sags, swells, voltage harmonics, imbalances and interruptions.…”