scholarly journals Capacitor Commutation Method for MVDC Hybrid Circuit Breakers

Designs ◽  
2021 ◽  
Vol 5 (2) ◽  
pp. 28
Author(s):  
Hyosung Kim
Keyword(s):  
Short Circuit ◽  
Circuit Breaker ◽  
Reverse Current ◽  
Resonant Circuit ◽  
Power Circuit ◽  
Power Sources ◽  
Semiconductor Switch ◽  
Current Commutation ◽  
Dc Circuit Breaker ◽  
Hybrid Circuit

The medium voltage DC (MVDC) type system can connect multiple terminals to a common MVDC bus, so it is possible to connect several renewable DC power sources to the common MVDC bus, but a DC circuit breaker is needed to isolate short circuit accidents that may occur in the MVDC bus. For this purpose, the concept of a hybrid DC circuit breaker that takes advantage of a low conduction loss contact type switch and an arcless-breaking semiconductor switch has been proposed. During break the hybrid switch, a dedicated current commutation device is required to temporarily bypass the load current flowing through the main switch into a semiconductor switch branch. Existing current commutation methods include a proactive method and a reverse current injection method by a LC (Inductor-capacitor) resonant circuit. This paper proposes a power circuit of a new MVDC hybrid circuit breaker using a low withstanding voltage capacitor branch for commutation and a sequence controller according to it, and verifies its operation through an experiment.

A State-of-the-Art 500-kV Hybrid Circuit Breaker for a dc Grid: The World's Largest Capacity High-Voltage dc Circuit Breaker

2020 ◽  
Vol 14 (2) ◽  
pp. 15-27
Author(s):  
Xiangyu Zhang ◽  
Zhanqing Yu ◽  
Rong Zeng ◽  
Yulong Huang ◽  
Biao Zhao ◽  
...  
Keyword(s):  
High Voltage ◽  
State Of The Art ◽  
Circuit Breaker ◽  
Dc Circuit Breaker ◽  
Hybrid Circuit

scholarly journals Short-Circuit Fault Current Calculation Method for the Multi-Terminal DC Grid Considering the DC Circuit Breaker

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1347
Author(s):  
Haipeng Jia ◽  
Jingyuan Yin ◽  
Tongzhen Wei ◽  
Qunhai Huo ◽  
Jinke Li ◽  
...  
Keyword(s):  
Calculation Method ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Fault Current ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Dc System ◽  
Short Circuit Calculation ◽  
Dc Circuit Breaker ◽  
Short Circuit Fault

The analysis and calculation of the short-circuit fault current in the DC grid is of great significance to the design and configuration of the converter station and DC circuit breaker parameters. The existing flexible DC system not only includes the modular multilevel converter (MMC) converter, but also needs power equipment such as the fault current limiter and DC circuit breaker. Therefore, the system modeling and short circuit calculation of the multi-terminal DC system after adding the DC circuit breaker are also of great significance for the design of DC power system parameters and the grid troubleshooting ability. In this paper, firstly, the parameters of the four-terminal DC system of the modular multilevel converter (MMC) are simplified, and the analytical solution of the short circuit fault current of the multi-terminal DC system is given. Then, the external characteristics of the cascaded hybrid DC circuit breaker are modeled. Based on the equivalent circuit of the fault current in different stages, the short circuit calculation method of four-terminal MMC system with DC circuit breaker is obtained. This method can effectively describe the overall trend of fault current and provide the basis for the configuration of DC line protection settings and DC circuit breaker related parameters.

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