Analysis of Four Options for High Voltage DC Circuit Breakers

As the science, economy and society, the advantages of direct current (DC) transmission in terms of transmission distance, stability, efficiency, and control are becoming more and more significant. At present, countries around the world are increasing the research and engineering application of DC transmission systems. Among them, a high-voltage DC circuit breaker (HVDC) is one of the protection facilities to ensure the stable transmission of high-voltage flexible DC, which is important for the realization of direct current transmission and new energy generation grid-connected technology and guarantees the reliable operation of DC power network and fault isolation. Unlike alternating current(AC) circuit breakers, DC have no natural zero crossing point for fault current. Therefore, the development of DC circuit breakers has received wide attention. At first, this paper introduces the research background of high-voltage DC circuit breakers, the current research status at home and abroad, and the main types. Then, it analyses the principles and corresponding topologies of four types of HVDC, namely, T-type modular DC circuit breaker (T-Breaker), a classic hybrid high-voltage DC circuit breaker topology proposed by ABB, hybrid high-voltage DC circuit breaker based on coupled negative voltage principle and Momentary Circuit Interrupter(MCI). Then, based on the system-rated voltage of 50 kV and fault transfer current of 2 kA, simulink simulation is used to obtain the corresponding waveforms to verify the feasibility. Among, a key analysis is conducted on MCI, and an improvement plan is proposed for its topology. Finally, the advantages and shortcomings of the above four HVDC and the outlook are summarized.