DVR Control Based on Stationary Reference Frame for Unbalanced Voltage Sag Compensation

Power quality problem in distribution system become more serious matter since the advancement in industrial equipment which require good power quality to ensure the sustainability of the production process. Voltage sag is one of the power quality problems that most probably happened caused by either normal or abnormal event in power system. Dynamic voltage restorer (DVR) can be chosen as a preferred approach to improve voltage quality at sensitive load locations. This paper proposes two control strategies to compensate the unbalanced voltage sag with enhance dq frame method with PI control and simplified αβ frame method with PR controller. The unbalanced voltage sag condition caused by single line ground fault (SLGF), which is most probably happened in distribution system, can be compensated well by these methods. Additional feature is coming from PR controller in αβ frame which plays an important role in performing better voltage tracking error, compared to PI controller in dq frame as an enhance comparison. PSIM simulation result has been presented to evaluate the effectiveness of the proposed method.