Application Research On DC Circuit Breaker Based On Resistance Type Superconducting Current Limiter

At present,VSC-HVDC DC transmission technology and DC distribution technology based on VSC are developing rapidly.However,due to the DC current does not cross zero,in the event of a fault can cause increased speed,high amplitude of short circuit current,this brings a new challenge to the fault breaking of the DC system,and the development of rapid turn-off of DC circuit breakers and the improvement of turn-off current levels have been written into the action plan of China's energy technology revolution and innovation.In order to solve the problem that the DC short circuit current is difficult to be cut off,this paper combines the superconducting current limiting technology with the DC breaking technology to study the DC circuit breaker based on the superconducting current limiting device.The following work is carried out in this paper:Firstly,this paper introduces the classification and research status of current superconducting current limiter and DC circuit breaker,and introduces the DC transmission and distribution technology,analyzes the necessity and urgency of research on DC circuit breaker based on superconducting current limiter.Secondly,this paper introduces and analyzes the basic principles of superconducting current limiter,DC arc,DC breaking,DC circuit breaker,DC circuit breaker control protection,DC fault,and makes a theoretical foundation for the research of DC circuit breaker based on superconducting current limiter.Thirdly,the topological structure of the DC circuit breaker based on the superconducting current limiter is designed,the electrical modeling and parameter selection of resistive type superconducting current limiter are carried out in MATLAB software,and the structural design and electrical modeling of the DC circuit breaker based on the superconducting current limiter are carried out.Finally,the 220 k V VSC-HVDC DC transmission system and 10 k V VSC-based DC distribution system were built in MATLAB,and the DC circuit breaker based on superconducting current limiter was connected to DC transmission and distribution respectively.The influence of DC circuit breaker based on superconducting current limiter on DC transmission and distribution network is studied.The research in the transmission network includes the voltage and current on the AC side of VSC at both ends,the voltage and current on the DC side,and the active power and reactive power on the AC side of VSC at both ends.The research in distribution network includes voltage and current of AC side,voltage and current of DC side,active power and reactive power of AC side.In addition,fault current limiting rate and turn-off time of DC circuit breaker based on superconducting current limiter are obtained.Simulation results show that SDCCB module can be connected to DC power grid.