Comprehensive Benefit Evaluation of Distributed Photovoltaic Power Generation System with DC Interconnection Based on Benefit-Cost Ratio

In recent years, the rapid development of distributed power supply and the outstanding advantages of DC distribution network lead to the project of integrating distributed photovoltaic (DPV) into DC network emerging at the right moment. Due to the related price reduction policy of PV power generation, the unmarketable price of the matched DC equipment, and the unclear impact of technical characteristics of DC grid-connection on system economy, it is necessary to establish an economical model combining the different operating modes of PV grid-connected system to evaluate the comprehensive benefit of system. Cost and benefit of PV power generation and DC distribution are considered, meanwhile the reliability and stability indicator of DC distribution are turning into power outage loss. Finally, cost and benefit of total life cycle are figured out. The result of the comprehensive benefit evaluation is characterized by the ratio, and the feasibility of the method is verified in a numerical example. Results show that the benefit of different operating modes varies greatly in the same scene. For residential low voltage DC (LVDC) power supply scene and urban intensive load area, the operating mode of unified purchasing and marketing is suitable, while industrial park are applied for self-use operating mode.