Research On The Grid-connected PV System Scheme

With the growing shortage of fossil minerals resources and air pollution problems are becoming increasingly prominent, the use of clean, low energy consumption, renewable energy has become a common pursuit of all over the world. In this situation, the photovoltaic power generation as a clean renewable energy has attracted the attention of many countries around the world. In recent years, photovoltaic power generation(generation PVG, photovoltaic) has been developed rapidly, and has been widely used in the world. PVG has three major characteristics: intermittent, periodic and random, and grid connected inverter, island effect and other factors, which affect the power quality of the power grid, as well as the reliability of power supply[1]. Large scale integration of large capacity grid connected photovoltaic power station and distributed photovoltaic power, to the power grid planning, operation and management brought a series of problems. At the same time, photovoltaic power generation is difficult to achieve complete scheduling of power system, the large-scale photovoltaic power station incorporated into the power grid will bring influence to the safe and reliable operation of power grid. Therefore, the grid connected photovoltaic system is of great significance to improve the reliability of grid connected system. In addition, in order to give full play to the advantages of PVG and reduce its adverse impact on the transmission network, it is necessary to analyze the impact of PVG access system power quality assessment. In view of the above problems, the main work is as follows:(1) Introduced to silicon photovoltaic cells, for example, the establishment of appropriate simplification and equivalence of the photovoltaic battery equivalent circuit; according to the manufacturers of photovoltaic array provides five important parameters, built the mathematical model reproduces the characteristics of photovoltaic array, for computer analysis of PVG characteristics. Detailed analysis of the impact of photovoltaic power generation access transmission and distribution grid on the protection and give solutions, and summarize the impact of photovoltaic power generation access distribution network on power quality.(2) For Zhangjiakou Huai Wang Hu Tun 20 mwp photovoltaic grid connected power generation project of case analysis, the PSD/BPA program analysis after the connection of the photovoltaic power flow distribution and short circuit current calculation, provide the basis for the design of electrical access scheme; design scheme also includes relay protection and automatic device configuration scheme, automation and communication configuration scheme.(3) According to the access system recommended program, according to the national standard and the use of BPA program and ETAP program to assess the impact of photovoltaic power station access to the system power quality.