Operation scheme for MMC-based STATCOM using modified instantaneous symmetrical components

Modular multilevel converters MMCs are characterized by modularization and multielectric equality, and the application of this structure to a high-voltage large-capacity static synchronous compensator STATCOM shows good potential. In this paper, a modified instantaneous symmetrical component method is proposed for positive- and negative-sequence decomposition, i.e. the critical part of the control device, which can accurately detect the instantaneous value of each sequence component in three-phase asymmetrical phasors in real time. Then, based on this method, the paper proposes a control method for MMC-based STATCOMs that solves the problems of multi-DC direct current voltage balance, grid-connected current control, and circulation suppression. Finally, the proposed detection and control methods are verified by performing simulations and experiments. The results show that the proposed method can quickly and accurately detect the positive- and negative-sequence reactive component that should be compensated by the device, thus realizing real-time reactive compensation for MMC-based STATCOMs.

___

  • 1] Robbins BA, Domínguez-García AD. Optimal reactive power dispatch for voltage regulation in unbalanced distribution systems. IEEE Transactions on Power Systems 2016; 31 (4): 2903-2913.
  • [2] Czarnecki LS, Haley PM. Unbalanced power in four-wire systems and its reactive compensation. IEEE Transactions on Power Delivery 2015; 30 (1): 53-63.
  • [3] Lee SY, Wu CJ. On-line reactive power compensation schemes for unbalanced three phase four wire distribution feeders. IEEE Transactions on Power Delivery 1993; 8 (4): 1958-1965.
  • [4] Tan YL. Analysis of line compensation by shunt-connected FACTS controllers: a comparison between SVC and STATCOM. IEEE Power Engineering Review 1999; 19 (8): 57-58.
  • [5] Pereira MMR, Ferreira CMM, Barbosa FM. Comparative study of STATCOM and SVC performance on dynamic voltage collapse of an electric power system with wind generation. IEEE Latin America Transactions 2014; 12 (2): 138-145.
  • [6] Tang Y, He H, Ni Z, Wen J, Huang T. Adaptive modulation for DFIG and STATCOM with high-voltage direct current transmission. IEEE Transactions on Neural Networks and Learning Systems 2016; 27 (8): 1762-1772.
  • [7] Haw LK, Dahidah MSA, Almurib HAF. SHE–PWM cascaded multilevel inverter with adjustable DC voltage levels control for STATCOM applications. IEEE Transactions on Power Electronics 2014; 29 (12): 6433-6444.
  • [8] Schön A, Hofmann V, Bakran MM. Optimisation of the HVDC auto transformer by using hybrid MMC modulation. IET Power Electronics 2018; 11 (3): 468-476.
  • [9] Lyu J, Cai X, Amin M, Molinas M. Sub-synchronous oscillation mechanism and its suppression in MMC-based HVDC connected wind farms. IET Generation, Transmission and Distribution 2018; 12 (4): 1021-1029.
  • [10] Bi T, Wang S, Jia K. Single pole-to-ground fault location method for MMC-HVDC system using active pulse. IET Generation, Transmission and Distribution 2018; 12 (2): 272-278.
  • [11] Kontos E, Tsolaridis G, Teodorescu R, Bauer P. High order voltage and current harmonic mitigation using the modular multilevel converter STATCOM. IEEE Access 2017; 5: 16684-16692.
  • [12] Strezoski VC. Advanced symmetrical components method. IET Generation, Transmission and Distribution 2011; 5 (8): 833-841.
  • [13] Ji FF, Khan MM, Chen C. Static var compensator based on rolling synchronous symmetrical component method for unbalance three-phase system. In: 2005 IEEE International Conference on Industrial Technology; Hong Kong; 2005. pp. 621-626.
  • [14] Elbouchikhi E, Choqueuse V, Feld G, Amirat Y, Benbouzid M. A symmetrical components-based load oscillation detection method for closed-loop controlled induction motors. In: 2017 IECON - 43rd Annual Conference of the IEEE Industrial Electronics Society; Beijing, China; 2017. pp. 8047-8052.
  • [15] Bau DF, Silva GSD, Pinheiro H, Grigolettol FB. PD modulation strategy for modular multilevel converters. In: IEEE International Conference on Industry Applications; Curitiba, Brazil; 2017. pp. 1-6.
  • [16] Singh M, Agarwal A, Kaira N. Performance evaluation of multilevel inverter with advance PWM control techniques. In: IEEE 5th International Conference on Power Electronics (IICPE); Delhi, India; 2012. pp. 1-6.
  • [17] Zhong Y, Roscoe N, Holliday D, Lim TC, Finney SJ. High-efficiency MOSFET-based MMC design for LVDC distribution systems. IEEE Transactions on Industry Applications 2017; 54 (1): 321-334.
  • [18] Moon JW, Kim CS, Park JW, Kang DW, Kim JM. Circulating current control in MMC under the unbalanced voltage. IEEE Transactions on Power Delivery 2013; 28 (3): 1952-1959.
  • [19] Barnklau H, Gensior A, Bernet S. Submodule capacitor dimensioning for modular multilevel converters. IEEE Transactions on Industry Applications 2014; 50 (3): 1915-1923.