Coupled Electromechanical Cost Optimization of High Speed Railway Overheads

This paper presents a coupled electromechanical optimization of the cost of high speed railway overheads. The proposed electromechanical optimization solves the coupled mechanical and electrical problems by obtaining the railway overhead with minimum cost. A simple model cost of the railway overhead is proposed. This model cost defines the global cost per kilometer, which is mainly composed by the costs of material used in the construction of the overhead supports and the electric lines respectively. Using a standard genetic algorithm the optimized railway overhead is obtained. The parameters which describe the railway overhead are defined by: (i) sizing and (ii) configuration of the overhead supports; (iii) geometric location and (iv) type of electric conductors. The constraints considered are: (i) maximum allowable stress, and (ii) structural static stability; (iii) structure gauge to limit the position of physical conductors, (iv) minimum distance between conductors or between conductor and earth and (v) maximum allowable current of each conductor. In addition, the fitness function also considers the minimization of the equivalent electrical system impedance as a secondary optimization criterion. This optimization method has been successfully applied to the design of the high speed railway overhead C-350, used in the new line Madrid-Barcelona-French Border. The optimized railway overhead shows an overall improvement at two levels. Firstly the performance is enhanced and secondly the global cost is reduced. The obtained results are compared with the non-optimized configuration in order to demonstrate the obtained improvements.