Worst-case identification of touch voltage and stray current of DC railwaysystem using genetic algorithm

The problem of reducing the touch voltage and stray cur lent in DC railways is multiobjective and conflicting. It is affected by many factors such as the earthing and bonding design, as well as the normal and failure operatin g conditions. An approach of genetic algorithm based multiobjective optimis ation is proposed to identify the worst-case touch voltage and stray curren t in MRT systems. A two-step design scheme is formulated to represent both the normal and the failure conditions. The method of Pareto-optimal sets is developed to best improve the touch voltages and stray current integral fo r the normal condition. The decision-maker is given a powerful tool for pic king the most appropriate earthing and bonding design from the set, and for identifying the worst-case performance from the list of credible failure c onditions. Simulation results are presented which demonstrate the effective ness of the proposed approach in fulfilling the design objectives.