| It is not only conducive to the low-carbon development of railroads and the promotion of rail energy internet construction,but also can promote the consumption of new energy in the surrounding area to achieve the goal of carbon peaking and carbon neutrality,which is the new energy access to the electrified railroad traction power supply system(TPSS).However,the application of new energy generation technology to the field of railroad traction is constrained by many factors,which is due to the special characteristics of China’s TPSS.At present,there is a lack of in-depth research on the impact mechanism of new energy into the TPSS,especially the impact of new energy into the TPSS on the power quality of the grid and other related content.Based on this,the following work was implemented regarding the above mentioned issues.(1)Modeling of new energy generation systems as well as TPSS.Firstly,based on the wind speed and light intensity distribution characteristics,the probabilistic model of wind power and photovoltaic power generation system is established,which is considering the randomness and fluctuation characteristics of wind power and photovoltaic power output.Secondly,based on the actual parameters,the traction substation,traction network and AT station are modeled respectively,and the simulation analysis of each part is carried out to verify the correctness of the model.Thirdly,based on the measured data,a probabilistic model of the active power of locomotives is established by probabilistic statistics of the active power of trains.Finally,Model of TPSS with new energy sources is established to lay the foundation for subsequent theoretical and simulation analysis.(2)The impact of new energy access on the voltage stability of the traction network is investigated.Firstly,the traction network voltage stability mechanism after new energy is connected to the TPSS is analyzed and used to find the factors that affect the traction network voltage stability after new energy is connected.Secondly,a traction network voltage stability indicator is established,which is based on the existence of a tidal current solution.Finally,based on the new energy access TPSS model,the tidal current calculation is carried out to obtain the system node voltage and branch probability tidal current distribution.The results of the tide calculation are used to analyze the impact of the new energy access capacity and access location on the traction network voltage,so that the traction network voltage stability boundary is obtained after the new energy access.(3)Analysis of the impact of new energy access to the TPSS on individual indicators of power quality of the grid.Firstly,the expressions for the relationship between the new energy access location,access capacity and the three-phase voltage imbalance,power factor and voltage deviation on the grid side are derived by theoretical analysis.Second,the new energy output and locomotive power are sampled by using Monte Carlo simulation method.The sampled data are used as input quantities for probabilistic tidal current calculation based on model of TPSS with new energy sources.Based on the information of voltage and branch currents at each node obtained from the tide calculation,indicators such as three-phase voltage unbalance,power factor and voltage deviation on the grid side are calculated.Finally,the simulation analyzes the impact of new energy access capacity and access location on individual indicators on the grid side.(4)The power quality of the power grid is evaluated for new energy access to the TPSS.Firstly,based on the weight characteristics of indicators,the comprehensive weight of each indicator is determined.Secondly,the power quality evaluation model is constructed based on the set-pair analysis method and variable fuzzy set.Finally,the power quality is evaluated according to the arithmetic analysis data.The evaluation results of the new energy access to the TPSS on the power quality of the grid are given. |
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