Convertible Unified Power Quality Conditioner to mitigate voltage and current imperfections


 This paper proposes a novel convertible unified power quality conditioner (CUPQC) by employing three voltage source converters (VSCs) which are connected to a multi-bus/multifeeder distribution system to mitigate current and voltage imperfections. The control performance of the VSCs is characterized by a minimum of six circuit open/close switches configurable in a minimum of seventeen combinations to enable the CUPQC to operate as shunt and series active power filters (APFs), unified power quality conditioner (UPQC), interline UPQC (IUPQC), multi-converter UPQC (MC-UPQC) and generalized UPQC (GUPQC). The simulation and compensation performance analysis of CUPQC are based on PSCAD/EMTDC.



Fig.1 Schematic representation of proposed CUPQC


 Fig.2. Feeder1 (a) Load current (b) Source voltage


 Fig.3. Feeder1 (a) Compensation currents (b) Compensation voltages

Fig.4. Feeder1 (a) Source currents (b) Load voltages

Fig.5. Feeder1 THD spectrum (a) Currents (b) Voltages

Fig.6. Feeder3 source voltage

Fig.7. Feeder3 compensation voltage

Fig.8. Feeder3 load voltages

Fig.9. Feeder3 voltage THD before and after compensation

Fig.10. (a) Feeder1source voltage (b) Feeder2 source voltage (c) Feeder3 load current

Fig.11. (a) Feeder1 compensation voltages (b) Feeder2 compensation

voltages(c) Feeder3 compensation currents

Fig.12. (a) Feeder1 load voltages (b) Feeder2 load voltages (c) Feeder3 source Currents

Fig.13. THD before and after compensation (a) Feeder1 voltage (b) Feeder2 voltage (c) Feeder3 current

Fig.14. RMS voltage (a) Feeder1 (b) Feeder2


In this paper the performance of the proposed CUPQC in three modes of operation as UPQC, MC-UPQC and GUPQC on a multi-bus/multi-feeder distribution system is validated by simulation results. The operating modes of the novel power quality conditioner in 17 different modes for compensation of currents and voltage interruptions are clearly explained. As an extension to this analysis, the authors are working on a model for characterization and testing of the proposed CUPQC.


 [1] H. Akagi, and H. Fujita “A new power line conditioner for harmonic compensation in power systems,” IEEE Trans. Power Del., vol. 10, 1995.

[2] P. Mitra, and G. Kumar, “An adaptive control strategy for DSTATCOM applications in an electric ship power system,” IEEE Trans. Power Electro., vol. 25, no. 1, pp. 95 –104, Jan. 2010.

[3] M. J. Newman, D. G. Holmes, J. G. Nielsen, and F. Blaabjerg, “A dynamic voltage restorer (DVR) with selective harmonic compensation at medium voltage level” IEEE Trans. Ind. Appl., vol. 41, no. 6, pp. 1744 – 1753, Nov. 2005.

[4] H. Fujita, and H. Akagi, “The unified power quality conditioner: The integration of series and shunt-active filters,” IEEE Trans. Power Electron., vol. 13, no. 2, pp. 315 – 322, Mar. 1998.

[5] V. Khadkikar, and A. Chandra, “A novel structure for three-phase four wire distribution system utilizing unified power quality conditioner,” IEEE Trans. Ind. Appl., vol. 45, no. 5, pp. 1897 – 1902, Sept./Oct. 2009.

Leave a Reply

Your email address will not be published. Required fields are marked *