Application of a new fast-responding estimation approach in DVR to mitigate voltage sags in harmonic distortion conditions

The main duty of a Dynamic Voltage Restorer (DVR) is protection of sensitive loads against voltage disturbances, especially voltage sags and swells. DVR should possess necessary response time in restoring load bus voltage to avoid load interruptions. One of the most important factors that affects the performance of DVR is the estimation approach which is used in control unit of this compensator. This paper presents a new fast-responding algorithm for the on-line estimation of symmetrical components in harmonic distortion conditions, which provides adequate response time and accuracy for dynamic voltage restorer. Furthermore, performance of this approach would be compared with some well-known estimation techniques. Application of the proposed estimation approach is realized in DVR by representing a new control unit for compensation of different voltage sags and swells. Finally, the simulation results, which obtained using PSCAD/EMTDC software package confirm efficiency of the suggested control unit.