Power Generation Output Prediction And Grid-Connected Analysis Of Photovoltaic System

With the dwindling traditional fossil fuels and increasing environmental pollution, frequent bad weather conditions have become global issues. Renewable and clean energy developments are gradually occupied the commanding heights of the national energy strategy. Solar energy is becoming a new generation of renewable energy for its wide distribution, inexhaustible, clean and safe, etc. The photovoltaic technology is one of the most promising use of solar energy technology. Photovoltaic grid-connected technology has become the main form of the PV application. With the growing capacity, PV system has an effect on existing power systems and PV system will bring a series of technical problems to the operation of the system.Firstly, the paper describes the working principle and feature of photovoltaic power generation systems and then analyzes the characteristics of input and output power, furthermore establishes a mathematical model of grid-connected photovoltaic power generation system. Based on the mathematical model, a grid-connected PV system electromagnetic transient model which includes photovoltaic array module, inverter module, maximum power point tracking module is established, and simulation results show the effectiveness of the PV array, MPPT control algorithms and the system model.Secondly, this paper puts forward two kinds of photoelectric output prediction method based on the research model of input and output characteristics. According to the structure and working principle of the photovoltaic system, it makes a full-time fitting on the local temperature and solar radiation where we cannot access to ambient parameters directly, and then to predict the output power of photovoltaic power generation system. Another way puts forward a method for per unit calculation of sunshine intensity and photovoltaic output based on the study of per unit. By combing with concrete example to launch meteorological factors influence coefficient, it predicts the output power of photovoltaic power generation systemFinally, the influence between the photovoltaic system and the power system is analyzed in detail through static and transient methods based on the actual power grid data. The main contents are as follows:the influence of PV system on power flow, voltage profile and transmission loss according to the different positions and capacity are analyzed, the technical suggestions and control strategy are proposed. Power system dynamic responses with sunshine variations are studied. It also analyses the influence of the photovoltaic system and the power system in the condition of network failure.