Title :
Voltage sag and swell generator with thyristor controlled reactor
Author :
Chung, Y.H. ; Kwon, G.H. ; Park, T.B. ; Lim, G.Y.
Author_Institution :
R&D Center, LG Ind. Syst. Co. Ltd, Kyunggi-Do, South Korea
Abstract :
This paper describes a new economical sag/swell voltage generator suitable for the evaluation of high power custom power devices such as DVR (dynamic voltage restorer) and DSTATCOM (distribution static compensator). Proposed system was designed to generate the several power quality disturbances in MVA power ratings-sag, swell, under voltage, over voltage and harmonic distortions. The sag and the under voltage can be generated by voltage drop across a reactor, while its magnitude and durations can be controlled by the firing angle of TCR (thyristor controlled reactor). In the case of the swell and the over voltage, we need a step-up transformer. Output of the step-up transformer is regulated by TCR to obtain nominal voltage level. At any given instant, if the firing angle of TCR is retarded or stopped, then we can obtain the swell voltage or the over voltage disturbance. Also we can generate harmonic current by controlling firing angles of TCR, while keeping the system voltage level within the specified limits. In this paper, two identical three-phase wye-connected TCRs are connected to the secondary windings of two step-down transformers, one operated from wye-wye transformer, the other from delta-wye transformer. Harmonic filters (11th and 13th) are added to reduce the voltage distortion when TCRs are operated. Simulation results are given for several cases of voltage sag and swell generations. Design guidelines are given for the TCR. Finally, conclusions are given.
Keywords :
harmonic distortion; overvoltage; power harmonic filters; power supply quality; power system harmonics; power transformers; reactors (electric); static VAr compensators; thyristor applications; transformer windings; 11th harmonic filter; 13th harmonic filter; DSTATCOM; DVR; MVA power ratings; custom power devices; delta-wye transformer; distribution static compensator; dynamic voltage restorer; firing angle; power quality disturbances; secondary windings; step-up transformer; three-phase wye-connected TCR; thyristor controlled reactor; voltage distortion reduction; voltage sag generator; voltage swell generator; wye-wye transformer; Harmonic distortion; Inductors; Power generation; Power generation economics; Power system economics; Power system restoration; STATCOM; Thyristors; Voltage control; Voltage fluctuations;
Conference_Titel :
Power System Technology, 2002. Proceedings. PowerCon 2002. International Conference on
Print_ISBN :
0-7803-7459-2
DOI :
10.1109/ICPST.2002.1067870