Research On Inter-line Dynamic Voltage Restorer

With the rapid development of modern science and technology, the level ofindustrialization is being strengthened. More and more sensitive load is used in theindustry and daily life, so it becomes more rigorous to the requirements of thepower quality. The transient power quality problems, such as voltage sags andInstantaneous interruptions of power supply, occur most frequently and cause thehuge economic losses. It arouses people’s concern. The Dynamic Voltage Restoreris the most common device to resolve the voltage sag of the sensitive load in theuser. The proposed of the Inter-line Dynamic Voltage Restorer can effectivelysimplify the complex structure of the Dynamic Voltage Restorers in many feeders.And it can make encapsulation and modularity, so it will be widely used in manyindustrial or commercial areas of many feeders. So the Inter-line Dynamic VoltageRestore is researched in this paper.For the realization of voltage compensation, the fast and exact detection ofvoltage sag amplitude and phase angle is important premise. According to theproblem of detection precision and response speed, this paper analyses three-phasesystem instantaneous reactive power theory based dq0transformation method andsingle-phase voltage sag αβ detection and the derivation constructing virtualcoordinate system is applied to the αβ transformation to improve detection precis ionand shorten the detection time. And the Butterworth IIR low pass filter is designedto improve the response speed of system and maintain the filtering effect. And iteffectively realizes the fast and exact detection of voltage sag.The working process and energy exchange princ iple of the Inter-line DynamicVoltage Restore is described in detail in this paper. Considering the economic,reliability and the application field, the main circuit topology of dynamic voltagerestorer and modules are analyzed and the selected. The selection of relatedparameters is derived in detail. For the stability of the DC side’s voltage, the PIcontroller is used to maintain stability and the resonant controller is used to reducethe steady-state error. Dynamic voltage restorer control process between the feedershas carried on the simulation, the simulation results verify the correctness oftheoretical analysis.Finally, the choice of the compensation strategy for the voltage compensationeffect plays a vital role. According to the different features of different types ofvoltage sags, this paper describes the merits and defects of the three basiccompensation strategies. Meanwhile it can be divided into no power consumptionmode and minimum power consumption mode according to the influence of the voltage sag amplitude and it can be divided into inadequate compensation mode andadequate compensation mode according to the influence of the DVR compensatingability. For the application of the minimum energy compensation, it will be carriedon the detailed research and the proper improvement to realize effectiveimplementation of the long time of full compensation. In the final, the simulation ofdifferent degree voltage sag and Instantaneous interruptions in the structure ofIDVR demonstrates the unique advantages of the structure. And it highlightsimportant economic value and application meaning.