Energy Optimization of Rail Transit Power Supply System with PVs and Energy Storage

In order to reduce the energy consumption of rail transit power supply, promote the local consumption of photovoltaic, and simultaneously, and improve the power supply flexibility of the system, this paper proposes an energy optimization method of photovoltaic and energy storage accessing to rail transit power supply system. Energy management model with minimal operating costs has been established. The constraints of power balance, the photovoltaic power, the battery state, photovoltaic and the grid transmission capacity were considered. A modified particle swarm optimization (MPSO) is used to optimize the solution. To verify the validity of the proposed method, an IEEE9 node system was used for the simulation test. The results show that the photovoltaic can be basically satisfied the traction load demand, when the light is sufficient and the passenger flow is small. Moreover in the load peak period, it is necessary to purchase electricity from the large power grid to maintain normal operation of the system.

I. Introduction

The traction power supply system is a relatively energy-intensive system. Recently, the scale of China's rail transit construction [1] has grown rapidly, and it will still be in a period of rapid development in the next decade [2]. The rapid development of rail transit has also increased the power supply voltage of the grid. Therefore, reducing energy consumption is a difficult problem [3] that must be solved in current rail transit power supply system [4].