Open AccessVirtual resistor circuit‐based control strategy of STATCOM during network unbalance
Author(s) -
Zhu Qiongfeng,
Li Qing,
Zhang Jinping,
Cheng Peng
Publication year - 2017
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2017.0642
Subject(s) - resistor , voltage , computer science , sequence (biology) , electrical engineering , control theory (sociology) , engineering , control (management) , genetics , artificial intelligence , biology
Static synchronous compensators (STATCOMs) have been widely used for the reactive power and voltage regulation in the renewable energy field. The STATCOM could not only regulate the positive‐sequence voltage component, but also suppress the negative‐sequence voltage by injecting the negative sequence current when the grid voltage is unbalanced. Aiming at diminishing the negative sequence voltage, the control strategy based on the symmetrical virtual resistor circuit is proposed in this study. The strategy is on the assumption that there are parallel virtual resistors connected to the point of interconnection (POI) of the STATCOM. It is theoretically proved that the negative sequence voltage can be eliminated when the current of the virtual resistors is balanced. Therefore, the negative sequence voltage can be eliminated by making the current of virtual resistors balanced. As the resistors are virtual in the real circuit, the voltage of the POI of the STATCOM is used in the input of the negative‐sequence current control loop instead of the current of the virtual resistors as the feedbacks. The signal of the ac voltages and currents of the STATCOM are only needed in this strategy which simplifies the system design. In the end, the simulation results are presented to validate the correctness and the effectiveness of the proposed control strategy.