Research On Distribution Network Reliability Evaluation Method With Distributed Photovoltaic Power Supply

As the terminal link of power system, the power supply reliability of power distribution system is closely related to the production and life of power consumers. Meanwhile, with increasingly serious energy crisis and environmental pollution, the distributed photovoltaic (PV) power generation technology gains more and more attention of the world by virtue of extensive sources, environmental protection and other advantages. However, with large access of distributed PV supplys, both the topology and power flow of the traditional distribution network change greatly, and different operations and configurations of the distributed PV supply yield serious influence on reliability of the distribution system. Therefore, it is necessary to perform accurate assessment and analysis on the reliability of distribution network with the distributed PV supply, so as to provide certain theoretical basis for future planning and construction of the distribution network and promote the rapid development of distributed PV industry. Aiming at the topology and running features of power distribution network, the dissertation focuses on the study of reliability assessment algorithm of distribution network with the distributed PV supply, and analyzes the reliability influence of distribution system with the distributed PV supply. The main work of the dissertation is performed as follows:1. A reliability assessment model of distribution network with the distributed PV supply is proposed. According to topological structure and running features of power distribution system, the reliability models of components and load of distribution system are deeply studied, the multi-state assessment model of the distributed PV supply is established by considering the randomness of output power of the distributed PV supply. Furthermore, the islanding principle and modeling approach of the distributed PV supply are studied, and thus establishes a theoretical foundation for the further research of the reliability of distribution network with the distributed PV supply.2. A new reliability assessment method suitable for the distribution network with the distributed PV supply is put forward, by analyzing the reliability assessment method for traditional distribution network, in which the network partition technology is combined with the node coding method, such that the failure influence analysis of the distribution system accessing the distributed PV supply can be greatly simplified. Moreover, the improved Monte-Carlo method is employed for sampling analysis and reliability assessment of the whole system, and an effective distribution system reliability computing method is thus established. An example verifies the effectiveness of the proposed method.3. The reliability influence factors of distribution network accessing the distributed PV supply are thoroughly analyzed. IEEE RBTS Bus6 example system is applied to calculate the reliability of different access capacities, access positions, synchronizing modes and operation modes of the distributed PV supply, and the obtained calculation results are further analyzed in quantitative and qualitative manner. As a result, the reliability influence factors of distribution network accessing the distributed PV supply are studied under different operations and configurations, which provides a theoretical foundation for the planning design of distribution network accessing the distributed PV supply.