Role of losses in design of DC cable for solar PV applications

This paper discusses the effect of losses in determining the optimal capacity of DC cable for a Solar Photovoltaic (PV) system application. The optimization problem is formulated to trade-off between the costs of losses against the cable investment cost over the operational lifetime of the cable. This is to minimize the total cost. The optimization problem is solved in closed form, clearly pointing out the key parameters that affect the optimal selection of DC cable. The main output of the model is the optimal cable capacity for a given PV system, as well as the relevant optimal utilization. The results are validated against the `heuristic´ approach of which the parametric analyses were carried out to determine the optimal cable rating. The findings suggest that the optimal utilization is likely to be very low driven by the paramount role of losses and the energy prices. Hence, the proposed model enables the PV system designer and the policy maker to gain meaningful insights on the parameters that affect the design of DC cable in solar PV system application.