Research On Photovoltaic Generation Technology And Its Ecnomic Performance In Electrified Railway

At present,Chinese railway is rapidly developing,which causes an increasingly serious energy consumption problem.The traction energy consumption in railway system accounts for the largest proportion of the total value,so reducing traction energy consumption is the key to reduce railway energy consumption.To achieve energy saving and emission reduction in railway system,the application of renewable energy has become an important measure.Photovoltaic(PV)generation has become one of the best choice because of its noiselessness,non-pollution and maintenance-free.Since the proportion of traction energy consumption is the largest,the most effective way to improve the energy consumption structure is to connect the PV generation system to the traction power supply system of the electrified railway through a reasonable way.Meanwhile,the traction load can directly consume PV power,which contirbutes to alleviate the accommodation problem of PV power.In view of the few researches on connecting PV generation system to traction power supply system,the following research has been done in this thsis.First,the basic principle of traction power supply and PV generation is introduced.In view of the particularity of two phase power collection of traction load of electrified railway,a back-to-back PV generation system based on single-phase back-to-back inverter is proposed,and its voltage and current double closed loop control method is established.PV energy utilization rate is proposed to evaluate the ablity of traction load to consume PV energy.The influence of PV integration on the power factor and negative sequence of the traction power supply system is also analyzed.Secondly,a series of optimization of back-to-back PV generation system has been carried out,which includes:(1)The power limit control of Boost circuit is introduced to restrict the output power of PV array,which contributes to eliminate the active power from back-to-back PV generation system to power system.(2)The control method of back-to-back inverter is improved,so that it can output different PV power to two arms of traction side,thus the PV energy utilization rate is greatly improved.(3)By configuring energy-storage(ES)system in back-to-back PV generation system,the PV energy utilization rate is further improved.At last,the ecnomic model of back-to-back PV/ES system under self-accommodation mode is established,considering efficiency,cost,benefit,attenuation,residual value and other factors.Based on net present value method,taking payback period and benefit-cost ratio as evaluation indexes,the economic performance of back-to-back PV/ES system under different system,cost,benefit parameters and different configuration plans is analyzed.The results are of certain guiding significance for investing back-to-back PV/ES system...