Cost-Effectiveness Enhancement in Distribution Networks Protection System Planning

The allocation of protective and controlling devices in distribution networks is a well-known optimization problem that has been addressed for over 20 years, while the coordination of these devices became a crucial issue in the last decade due to the insertion of distributed generators in the systems. Prior researches have proposed either solving the allocation considering coordination indications or the decoupled approach of these problems. However, the first is not suitable for active systems, and the latter fails to achieve high-quality solutions due to topology changes during the coordination adequation. This paper presents an optimization model that combines both allocation and coordination as a single problem, considering technical and economic aspects. We consider the system's uncertainties and the generators' limits of current injection during fault situations. The proposed methodology also allows planning the protection system considering only the most common fault scenarios. The sitting of devices is handled by a genetic algorithm, while the coordination is guaranteed by a linear model that runs within the metaheuristic. The tool is tested for a real 135-bus distribution system.