Analysis Of The Key Factors And Optimization In Economic Operation Of Distributed Generation System

With the rapid rise of new energy power generation, distributed power system begins to flourish. As a supplement to large power grids, distributed power generation system can improve reliability of power supply and reduce investment costs. Especially in remote mountainous areas, the distributed power system has great significance in the aspect of improving reliability of power supply, protecting the ecological environment and improving the system benefits.Wind power and photovoltaic power generation has a very good complementary characters. At the same time, the energy storage device is an important part of distributed generation system, which can further improve the power supply reliability of distributed generation system. What are the key factors to optimize the operation by the distributed generation system and how to optimize the distributed system in the planning level and operation level are the two core issues of this article. Around the two issues, the main work is as follows:(1)The influence factors of the system economic operation is analyzed and the optimization mode is establishedThis thesis analyzes the influence of all factors of the system economic operation from the planning level and operation level. Based on these factors, the system optimization model is established which considering the electricity sales revenue, investment cost, environmental benefits and economic losses of power users. This model is a macro model which not only considers the costs and benefits of distributed generation system, but also considers the environment influence of distributed systems bring to the society. At the same time, system outage punishment cost is added to the objective function, which can improve the proportion of power supply reliability in the optimization goal and make the system more reliable.(2) The complementary characteristics of the wind and solar is analyzed and the wind turbine and photovoltaic capacity are optimizedBased on the complementary characteristics of the wind and solar, the capacity of wind turbine and photovoltaic are optimized. And then, the sensitivity of the factors influencing on the system economic is analyzed. According to the nature of the factors, the influence factors are divided into positive and negative factors. And according to the absolute value of the coefficient of factors, the factors are divided into key factors, second key factors and non-critical factors.(3) The energy storage capacity is optimized and the sensitivity of the factors influencing on the system economic is analyzedBased on the capacity of wind turbine and photovoltaic optimized, the capacity of storage is optimized. Using power function fitting method to fit the curve of the charge-discharge cycle life of energy storage, and using the rain-flow-counting method to equivalent the charging and discharging times of the energy storage. According to the contrast of indicators between the system with storage and without storage, the change of indicators and economic could be cleared. Comparison results show that the comprehensive income and operation indicators are all be improved after the system installed comfortable energy storage system. At the same time, the sensitivity of the factors influencing on the system economic is analyzed(4) Optimal fuzzy control method is designed considering the energy storage SOC and cycle lifeConsidering the relationship between storage SOC and cycle life, a fuzzy control method is designed which reveals the problem that frequent and deep charging and discharging may reduce the battery cycle life. A fuzzy controller is designed which including power allocation part and power correction part, to optimize the battery charging and discharging control. Comparison results show that the system total revenue increased significantly by using fuzzy control method.