Study On Topology And Reliability In DC Distribution Network

With the development of economy and the improvement ofpeople’s living standards, the contradiction between the growing load and the limits of the corridor’s transmission power gradually emerges. The existing AC distribution network in China has the deficiency of small power supply radius and limited supply capability, and is insufficient to meet the requirements for the distribution network of future society. The DC distribution network by contrast has the advantages of lower line cost, larger transmission capacity, farther power supply range, smaller power loss, higher power quality and higher conversion efficiency, etc., and becomes the direction of future distribution network.The topology and reliability of DC distribution network is researched in this paper. Starting from the connection and operation of the components in distribution network, on the basis of the structure of communications system, marine system, metro electric traction system, aerospace power system and mature AC system and the characteristics of DC distribution, the feasible topology of hybrid AC-DC power distribution system and pure DC power distribution system is proposed, and the operation of ring network is compared and analyzed.Through the comparison and analysis of the assessment methods of reliability model, Sequential Monte Carlo that can be used for real-time simulation on the power grid is selected in this paper. The fault traversal method is used to search on the fault and load twice to ensure the accuracy and speed of calculation. And the method of counting reliability index is improved through the load classification.At last, the model and algorithm proposed in the paper is applied to the typical case of IEEE RBTS Bus-6. The model and algorithm is verified to be scientific and accurate through the calculation of the reliability of the system and the load in AC mode. The case and algorithm is used and the reliability index is calculated in DC distribution network while the adaptability of power electronic devices is analyzed, and ultimately a detailed analysis of the results is shown in this paper.