Power conditioning using dynamic voltage restorers under different voltage sag types

Abstract

Voltage sags can be symmetrical or unsymmetrical depending on the causes of the sag. At the present time, one of the most common procedures for mitigating voltage sags is by the use of dynamic voltage restorers (DVRs). By definition, a DVR is a controlled voltage source inserted between the network and a sensitive load through a booster transformer injecting voltage into the network in order to correct any disturbance affecting a sensitive load voltage. In this paper, modelling of DVR for voltage correction using MatLab software is presented. The performance of the device under different voltage sag types is described, where the voltage sag types are introduced using the different types of short-circuit faults included in the environment of the MatLab/Simulink package. The robustness of the proposed device is evaluated using the common voltage sag indices, while taking into account voltage and current unbalance percentages, where maintaining the total harmonic distortion percentage of the load voltage within a specified range is desired. Finally, several simulation results are shown in order to highlight that the DVR is capable of effective correction of the voltage sag while minimizing the grid voltage unbalance and distortion, regardless of the fault type.

Effect of Distributed Wind Generation on the Voltage Sag of Distribution Networks

“…DVR is normally connected between the point of common coupling (PCC) and feeder load in the distribution network. DVR is composed of the following basic elements [14]:…”

Power quality improvement using dynamic voltage restorer in distribution system PT. DSS Power Plant

“…DVR is a power electronic switching device which is connected in series to the load voltage bus to inject a dynamically controlled voltage. This voltage can eliminate effects of fault of voltage bus on a sensitive load [6].…”

“…The dq0 method will provide information on the depth of the voltage drop and the phase shift with the starting point and end point of the voltage drop. The transformation process from three phase system to dq0 system is shows at Equation 1 [6].…”

Introductory Chapter: Power System Harmonics—Analysis, Effects, and Mitigation Solutions for Power Quality Improvement

“…The IEEE 112 [9] defines the voltage unbalance using a factor called the phase voltage unbalance rate (PVUR), is given in (2), where V dev expresses the phase voltage variation from the average line voltage (V average ) [10].…”