Research On The Technology Of DC Power Supply At Safety Voltage For Civil Buildings

With the growing of distributed renewable energy generation,the development of power electronics technology,and the increase of the DC load ratio,the DC forms in the links of low-voltage power supply system,such as generation,conversion and consumption,are increasing day by day.The superiority of DC power supply is prominent.Based on this,considering the obvious advantages of DC power supply in civil buildings,the broad market prospects,and the current situation of building electricity safety which is urgently to be improved,some related research has studied it and introduced extra-low voltage level to improve power safety.However,existing projects are still in the demonstration stage,and the unified standard for safety voltage has not formed.Whether it can meet the needs of civil buildings is still unknown,and the main problems at the application level involving its safety and economy need to be solved.Therefore,exploring the feasibility of the safety voltage DC power supply for civil buildings and solving the characteristic problems are crucial to the development of the DC power supply field in civil buildings.Based on this,this article has carried on the research and the main results are as follows:First,combining the civil building scene,the security requirements and power supply capacity requirements are analyzed.Then,the range of safety voltage and reasonable value that can meet the requirements of both sides are determined.The concrete application scheme in typical scenes of residential buildings and office buildings is given,and the feasibility of safe voltage DC power supply in civil buildings is proved.Afterwards,according to the high safety and economic requirements in civil buildings,the two main problems in the application of safety voltage DC power supply,arc protection and capacity optimization,were studied respectively.One is arc protection under safety voltage level.First,the essential characteristics of the DC arc are elaborated in detail.Based on this,the steady and dynamic characteristics in different circuits are analyzed.Then,the theoretical analysis is verified by experiments and the relevant data is supplemented.Finally,based on the experimental results,some design suggestions are put forward for arc protection,which makes it possible not to install an arc fault detection device.It is of great significance for improving the safety and economy of the system.The second is the power capacity optimization of the system on safety voltage.First,by exploring the characteristics of electricity demand of civil buildings,the capacity design difficulty caused by the small power supply distance of extra-low voltage is clarified.Based on this,the idea of paralleling the power supply is proposed and its capacity expansion ability is estimated.Then based on the requirements of the parallel system,a topology of the parallel power supply through the interface circuit and an improved droop control method are proposed.Finally,a parallel power supply experimental platform is built to verify the stability of the system operation under this topology and the effectiveness of the control method.