Study On Risk Assessment Of Self Consistent Energy System For Rail Transit Considering PV Access

China has the largest rail transit network in the world.Currently,rail transit is highly electrified,and its carbon emissions are high from a full life cycle perspective.According to the "Outline of Building a Strong Transportation Country"and the dual carbon goal,rail transit needs to evolve in three major directions:green,flexible,and intelligent energy use.The integration of energy and transportation is the trend of the times.Transforming rail transit’s own resources into energy will greatly reduce carbon emissions if it can fully meet the energy needs of rail transit and form a self consistent energy system for rail transit.Connecting photovoltaic power to the traction power supply system is conducive to the formation of a self consistent energy system for rail transit.However,there is uncertainty in the output of photovoltaic power,and there is also strong volatility in the traction load.How to formulate an operational strategy for a self consistent energy system for rail transit under two-way uncertainty in supply and demand is a bottleneck issue that needs to be addressed urgently.In addition,considering that the rail transit self consistent energy system is the only power source for trains,especially after photovoltaic access,the operational risk of the system increases,and once a failure occurs,it may lead to train delays or outages.In order to ensure the safe and stable operation of the system,it is necessary to conduct a risk assessment study on the rail transit self consistent energy system.Focusing on the above issues,the main work of this article is as follows:(1)In order to solve the problem of photovoltaic output uncertainty,an improved light robust model considering the risk cost of photovoltaic output was proposed.This model started with an uncertain set and realized the collaborative optimization of risk cost and operating cost by analyzing the objective function in the improved light robust model;In order to solve the problem of low utilization efficiency of regenerative braking energy,an energy storage type regenerative braking energy utilization model considering the impact of time-of-use electricity prices is proposed.By analyzing the generation characteristics of regenerative braking energy,the characteristics of high peak hour electricity prices and low valley hour electricity prices of time-of-use electricity prices are considered,and the efficient utilization of regenerative braking energy is achieved.(2)In order to solve the problem of time resolution mismatch between supply and demand data caused by traction load fluctuation,a power supply and demand balance uncertainty model considering traction load fluctuation was proposed.The model first constructs the main problem with the minimum operating cost plus risk cost as the objective function,and then uses two load checks to modify the solution results of the main problem from a second level time scale from the perspective of photovoltaic absorption.The analysis of a numerical example shows that the proposed model can adapt to the fluctuations of traction load on a second level time scale,providing a reference for the formulation of operational strategies for rail transit self consistent energy systems.(3)In order to solve the risk assessment problem of self consistent energy systems in rail transit,a risk assessment method based on the idea of risk matrix was proposed.This method quantifies the risk consequences and probability,constructs a risk weight matrix,and achieves the classification of risk sources for equipment.Finally,the number of various risk sources existing in operation can be intuitively found through the system’s risk source matrix.