Research On 20MW Photovoltaic Power Generation System And Design

As the world economy development and social progress, human demand for energy is more and more big, and the environmental pollution is becoming more and more serious. Traditional energy reserves, such as oils,coals,and so on,is declined.Solar energy is a clean renewable energy,and the research on photovoltaic power generation system is of great significance. Based on the solar energy resources and engineering geological conditions of Zhuzhou city in Hunan province, the research on 20 MW photovoltaic power generation system and design are carried on, and the main research contents are as follows.(1) The grid photovoltaic system type of AC busbar is adopted, the mode of block power generation and centralized grid connection are used in the overall scheme of the system. The 260 W polysilicon solar modules are chosen, the fixed installation method is adopted in operation control of photovoltaic array, and the best inclined angle of photovoltaic array is 23 degree, 500 kw grid connected inverter is with maximum power point tracking(MPPT). The results of design and calculation show that the total capacity of photovoltaic power is 20.03 MW, average annual power in plant operating period is 17.954 million k W·h, annual utilization hours of equivalent full load is 896.4h, capacity coefficient is 0.102.(2) The main electrical connection of 35 k V switch station of electric primary system is designed. The 35 kv side connection mode of switching station is single busbar connection, sets of wire cables of photovoltaic power station are selected, and grounding system of 380/220 v three phases and four wires is used in station power source system.The main equipment selections and calculations of electric primary system are carried on, the lightning protection, earthing and overvoltage protection, lighting, etc.are designed,the equipment arrangements of electric primary system are made.(3) The secondary electrical system and communication system are designed.The pattern of "Unmanned on duty(few unattended)" is adopted in computer monitoring system of switching station, and the structure of hierarchical distributed system is used in monitoring system.On-situ monitoring protection of grid inverter is mainly carried on by its complete set of measurement,control and protection devices, and centralized monitoring of grid inverter is achieved by computer monitoring system.The microcomputer protection devices are selected in relay protection and automatic devices of main electrical equipments(35kv bus,35 kv circuits, etc.),and a comprehensive way of telecontrol and monitoring system is used in dispatching automation system. Power information sharing in station is adopted in integrated power system of AC/DC,and control station,cameras, video cable, control cable,etc. are included in video security monitoring system.The method of centralized equipment layout is used in secondary electric system, and communications in system and within the station are analyzed and designed.(4) The analysis of energy saving and consumption of system is carried on. By selecting energy-saving equipments and products, all kinds of measures of energy saving and consumption of main electrical equipments are adopted, annual average 17.954 million k W·h of clean electric energy can be provided in the system,the consumption of fossil resources can be reduced,and it is beneficial to alleviate the pressure on environmental protection.The harmonious development between economy and environment can be realized,and energy-saving and environmental benefit are well.