| Global warming and energy exhaustion make the distributed power and new energy products have been vigorously promoted and developed.The development of power electronic technology makes the number of DC load on the user side of the power system increase.These changes make people pay more attention to the DC distribution system.The main research object of this paper is the low-voltage DC distribution system in residential areas.PSCAD software is used for the characteristics of residential areas The research is divided into three parts:(1)Firstly,according to the overall situation of the residential area,the overall structure of the DC distribution system in the residential area is studied: voltage level,wiring mode,composition unit,key equipment and devices,etc.Finally,the voltage level of 10 kV,750V and 400 V and symmetrical single polarity layered bus structure are determined,and photovoltaic cells,batteries,electric steam are used Vehicle charging pile and AC/ DC load are the main loads;(2)Then,the control scheme of each part of DC distribution system in residential area is studied by simulation: the control scheme design of each main unit,the overall model building,and the simulation under the different working conditions of normal operation,photovoltaic power generation conditions change and negative load wave,which proves that the system has certain feasibility;(3)Then the protection scheme of DC distribution system in residential area is explored: analysis and modeling calculation of various fault types,research and Simulation of neutral point grounding mode of capacitor,design and Simulation of relay protection scheme,analysis of user side grounding protection.It can be seen that under the above protection scheme,the system has certain reliability.With the maturity of DC circuit breaker and fault current limiter and other protection devices,Its fault protection will be more developed to meet the distribution requirements of residential areas. |
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