| The space solar power station system is a device that transmits solar energy from space to the ground,whose operating position is the synchronous satellite orbit.Its energy conversion efficiency is several times larger than that of the ground photovoltaic power generation system,in which way,it can provide safe and independent renewable energy.The large-scale development and utilization of space solar power station is a way to excavate clean energy as well,which is of great significance to the early realization of China ’s "Peak CO2 Emissions and Carbon Neutrality" goal.However,the environment of the space solar power station is quite different from the ground power station,so the operating conditions of each device in the SSPS will also change greatly.Due to the nonexistence of zero-crossing point in DC system,it is of great difficulty to break the DC circuit even in power system of land surface,which means high voltage and high-power DC circuit breaker is a very important technical problem.Except that,in the aerospace environment,it not only requires fast enough breaking speed,but also needs to have the ability to adapt to the harsh temperature and radiation environment in space.In addition,it also needs to meet the requirements of quality,volume and long life,which poses a great challenge to the space high-voltage and high-power DC current-limiting breaking technology.DC solid-state breaking technology based on power electronic devices and hybrid DC breaking technology are the key development directions in the future.Based on this situation,this paper studies the space high-voltage current limiting technology in the space solar power plant system,and explores a fault current limiting prototype that can be automatically detected and automatically disconnected.The fault current limiting breaking and protection control prototype is mainly studied from three aspects:current limiting topology,breaking structure and protection control strategy.In view of the defects of the existing current limiter,such as the inability to automatically detect and remove faults,the inability to two-way energy transfer,and the high loss,high cost and poor efficiency,four types of fault current limiter topology are designed,including series fault current limiting topology,bidirectional series fault current limiting topology,coupled inductor fault current limiting topology and a new type of twoway fault current limiting topology.By means of analyzing the structure and working principle of these four types of fault current limiting topologies,parameters of each component in each topology are calculated,and the simulation analysis of working characteristics is carried out for each topology in Multisim simulation software as well.Through the comparative analysis of four fault current limiting topologies,it is found that the new type of two-way fault current limiting topology can realize automatic breaking action without external drive and avoid the risk of failure in the idle station environment.In order to ensure that the fault current can be removed in time,except the design and research of the fault current limiting topology,the reasonable design of the breaking structure of the fault current limiter is necessary as well.The regular breaking structure of fault current limiter including mechanical,all solid and hybrid three categories,but as mentioned before,the space environment of space solar power station is more complex.In the high voltage and high-power environment,there may be various problems in power electronic switching devices,such as voltage division and split flow,overvoltage and overcurrent,etc.Therefore,in this paper,a junction capacitive breaking structure is proposed.Combining the junction capacitive breaking structure with the new bidirectional fault current limiting topology described above,and then adopting appropriate protection control strategy,the fast and low loss operation of the fault current limiter can be achieved.Except the two aspects above,the protection control strategy of the current limiter prototype is studied,and the influence of the current limiter on the three conventional protection strategies of current protection,distance protection and zero sequence current protection is analyzed in this paper.The protection control strategy suitable for space solar power station is proposed,and the fault signal sampling and extraction method is studied.So as to verify the effectiveness and feasibility of the research in this paper,this paper uses simulation software to compare the new current limiter topology,junction capacitive breaking structure and fault transient feature extraction method with typical methods,and verifies the advantages of this design through quantitative data and key waveform testing.The research results show that the new current limiter topology studied in this paper can realize automatic detection and automatic disconnection,and has the characteristics of low loss,while the junction capacitive breaking structure can also avoid the overshoot interference of the traditional breaking structure. |
