This paper proposes a hybrid static synchronous compensator (hybrid-STATCOM) in a three-phase power transmission system that has a wide compensation range and low DC-link voltage. Because of these prominent characteristics, the system costs can be greatly reduced. In this paper, the circuit configuration of hybrid-STATCOM is introduced first. Its V-I characteristic is then analyzed, discussed, and compared with traditional STATCOM and capacitive-coupled STATCOM (C-STATCOM). The system parameter design is then proposed on the basis of consideration of the reactive power compensation range and avoidance of the potential resonance problem. After that, a control strategy for hybrid-STATCOM is proposed to allow operation under different voltage and current conditions, such as unbalanced current, voltage dip, and voltage fault. Finally, simulation and experimental results are provided to verify the wide compensation range and low DC-link voltage characteristics and the good dynamic performance of the proposed hybrid-STATCOM.
- Capacitive-coupled static synchronous compensator (C-STATCOM)
- Hybrid static synchronous compensator (hybrid-STATCOM)
- Static synchronous compensator (STATCOM)
- Wide compensation range
- Low DC-link voltage
Fig. 1. Circuit configuration of the hybrid-STATCOM.
EXPECTED SIMULATION RESULTS:
Fig. 2. Dynamic compensation waveforms of load voltage, source current, and load and source reactive powers by applying hybrid-STATCOM under different loadings cases.
Fig. 3 Dynamic compensation waveforms of vx and isx by applying hybrid-STATCOM under (a) inductive load, (b) capacitive load and (c) changing from capacitive load to inductive load.
Fig. 4. Dynamic compensation waveforms of vx and isx by applying hybrid-STATCOM under unbalanced loads.
Fig. 5. Dynamic compensation waveforms of vx and isx by applying hybrid-STATCOM under voltage fault condition.
Fig. 6. Dynamic compensation waveforms of vx and isx by applying hybrid-STATCOM during voltage dip.
In this paper, a hybrid-STATCOM in three-phase power system is proposed and discussed as a cost-effective reactive power compensator for medium voltage level application. The system configuration and V-I characteristic of the hybrid-STATCOM are analyzed, discussed, and compared with traditional STATCOM and C-STATCOM. In addition, its parameter design method is proposed on the basis of consideration of the reactive power compensation range and prevention of a potential resonance problem. Moreover, the control strategy of the hybrid-STATCOM is developed under different voltage and current conditions. Finally, the wide compensation range and low DC-link voltage characteristics with good dynamic performance of the hybrid-STATCOM are proved by both simulation and experimental results.
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