An Extended Mathematical Programming Model to Optimize the Cable Trench Route of Power Transmission in a Metro Depot

The necessary electricity of the workshops and buildings (W&Bs;) located at the metro depot are provided by lighting power substation (LPS). To transmit electricity between LPS and W&Bs;, some trenches should be dig and the requisite cables should be located in the trenches. This paper presents a new mixed integer linear programming (MILP) long-term decision model to find the best cable trench route between LPS and W&Bs; and also the location of all W&Bs; and LPS are fixed. In this problem, the objective is to minimize (1) used cables cost, and (2) trench digging cost. It should be considered that there exist many cases in which the minimum either used cables or trench digging does not result in minimum total cost. Therefore, in optimum solution, a tradeoff between these objectives should be achieved. Finally, the proposed model is applied to a real case study at the metro depot in Iran and the optimum solution is analyzed.