Optimal commitment of frequency converter units for railway power supply

Abstract

This paper describes a method for the optimal starting and stopping of railway frequency converter units. This involves solving the unit commitment problem, whereby the rotary converters can be in three modes of operation: disconnected; in full operation; or in idle rotation with only the motor connected. With appropriate assumptions, it is shown that sections of the railway contact line can be considered separately from each other, which greatly reduces the dimension of the overall optimization problem, enabling several small problems to be solved instead using a full dynamic programming algorithm. A fast power flow calculation method is used to obtain power injections for each converter station at every time step. Numerical examples confirm the applicability of the proposed algorithm.