Amin Jamili - Assistant Professor, School of Industrial Engineering, University of Tehran, Tehran, Iran
Farshad Ramezankhani - MSc. Student, School of Industrial Engineering, University of Tehran, Tehran, Iran

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

Cable trench problem, lighting power substation, metro depot, optimization