铁路沿线光伏供电系统优化设计方法研究

Optimization of photovoltaic systems along railways

离网式太阳能光伏系统是解决铁路沿线设施电气化运维用电需求的必要途径。《光伏发电站设计规范》(GB 50797―2012)等相关规范的规定或建议一般以年最大发电量为目标,主要面向均衡性负载和并网发电,直接用于铁路沿线时存在盲目性。针对铁路沿线特殊的用电场景与负载需求,提出了铁路沿线离网式光储系统的组件匹配原则及设计流程,构建了面向任意时间跨度的光伏供电系统优化设计模型,并基于Python语言编制了计算程序。模型包括太阳辐照量模型、光伏阵列倾角及间距模型、发电量模型、光伏组件数量及串并联方案模型、蓄电池模型、控制器模型及逆变器模型等。计算程序实现了光伏阵列最优倾角的自动搜索,可以针对不同地理位置、用电量和用电时间跨度(月、季节、年等)的负载需求,并考虑气象条件、组件性能衰减等因素的影响,完成光储系统的设计选型和安装方案优化。在准池铁路的实际应用表明,一年中光伏阵列在各月对应的最优倾角存在明显差异,6月达到最小值16°,12月达到峰值69°。以全年、夏半年、冬半年的最大总辐照量为目标时,最优倾角分别为46°、25°、61°。对于案例中冬季型负载,采用基于本文模型的设计方案相比规范建议方案节省投资8.8%。研究成果可为铁路沿线光伏供电系统应用提供一种便捷的设计方案。

Off-grid solar photovoltaic system is an innovative way to supply power for electrified operations and maintenance of facilities along railways.The provisions or recommendations of specifications such as the Code for Design of Photovoltaic Power Station(GB 507972012)and other relevant standards generally target the maximum annual power generation capacity,which is mainly oriented to balanced loads and grid-connected power generation,and there is a blindness when it is directly used for railroad lines.In this paper,for the special power scenario and load demand along the railroad line,the component matching principle and design process of an off-grid photovoltaic storage system along the railroad line was proposed,the optimal design model of photovoltaic power supply system for any period was constructed,and the calculation program was compiled based on Python language.The model included a solar irradiation model,PV array tilt angle and spacing model,power generation model,PV module quantity and series-parallel connection scheme model,battery model,controller model,and inverter model.The calculation program realized the automatic search for the optimal tilt angle of the PV array,which can complete the design selection and installation scheme optimization of the optical storage system according to the load demand of different geographic locations,power consumption,and power consumption period(month,season,year,etc.),as well as considering the influence of meteorological conditions,module performance degradation and other factors.The practical application in the Junchi Railway shows that there is a significant difference in the optimum inclination angle of photovoltaic arrays at different months of the year.More specifically,the minimum and maximum angles are 16°and 69°,which occurs in June and December,respectively.To absorb maximum radiation throughout the whole year,summer half-year and winter half-year,the optimum inclination angles are 46°,25°,and 61°,respectively.For the winter-type load,the optimized scheme can save 8.8%of investment compared with the scheme recommended by the specification.The research results can provide a guideline for designing photovoltaic power systems along the railway.