The Dynamic Voltage Restorer (DVR) is an electronic power device that is used to inject three-phase voltage in series and in sync with the voltages of the distribution feeder to compensate for voltage sag. This work presents the operation of a DVR. The power circuit of a DVR is explained along with the control techniques used for the compensation. The software phase lock loop (SPLL) and its stability are analyzed. The DVR control system is described and verified using simulation.
Dynamic voltage restoration (DVR) is a method to overcome the voltage losses that occur in the distribution of electrical energy. These are a problem because the peaks consume energy and reduce the efficiency of some devices. DVR saves energy through voltage injections that can affect the phase and waveform of the power being supplied.
Devices used for DVRs include static var devices, which are serial compensation devices using voltage source converters (VSC). The first such system in North America was installed in 1996 - a 12.47 kV system located in Anderson, South Carolina.